@@ -1,7 +1,7 @@
11{-|
22Module: Squeal.PostgreSQL.Query
33Description: Squeal queries
4−Copyright: (c) Eitan Chatav, 2019
4+Copyright: (c) Eitan Chatav, 2017
55Maintainer: eitan@morphism.tech
66Stability: experimental
77
@@ -9,81 +9,74 @@ Squeal queries.
99-}
1010
1111{-# LANGUAGE
12− ConstraintKinds
13− , DeriveGeneric
12+ DeriveGeneric
1413 , FlexibleContexts
1514 , FlexibleInstances
1615 , GADTs
1716 , GeneralizedNewtypeDeriving
1817 , LambdaCase
1918 , MultiParamTypeClasses
20− , OverloadedLabels
2119 , OverloadedStrings
22− , QuantifiedConstraints
23− , ScopedTypeVariables
2420 , StandaloneDeriving
25− , TypeApplications
2621 , TypeFamilies
2722 , TypeInType
2823 , TypeOperators
29− , RankNTypes
3024 , UndecidableInstances
31− #-}
25+#-}
3226
3327module Squeal.PostgreSQL.Query
3428 ( -- * Queries
35− Query_
36− , Query (..)
37− -- ** Select
38− , select
39− , select_
40− , selectDistinct
41− , selectDistinct_
42− , selectDistinctOn
43− , selectDistinctOn_
44− , Selection (..)
45− -- ** Values
46− , values
47− , values_
48− -- ** Set Operations
29+ Query (UnsafeQuery, renderQuery)
4930 , union
5031 , unionAll
5132 , intersect
5233 , intersectAll
5334 , except
5435 , exceptAll
55− -- ** With
56− , With (..)
57− , CommonTableExpression (..)
58− , withRecursive
36+ -- * Select
37+ , select
38+ , selectDistinct
39+ , selectStar
40+ , selectDistinctStar
41+ , selectDotStar
42+ , selectDistinctDotStar
43+ , values
44+ , values_
5945 -- * Table Expressions
6046 , TableExpression (..)
47+ , renderTableExpression
6148 , from
6249 , where_
6350 , groupBy
6451 , having
52+ , orderBy
6553 , limit
6654 , offset
67− -- * From Clauses
55+ -- * From
6856 , FromClause (..)
6957 , table
7058 , subquery
7159 , view
72− , common
7360 , crossJoin
7461 , innerJoin
7562 , leftOuterJoin
7663 , rightOuterJoin
7764 , fullOuterJoin
7865 -- * Grouping
79− , By (..)
80− , GroupByClause (..)
81− , HavingClause (..)
66+ , By (By1, By2)
67+ , renderBy
68+ , GroupByClause (NoGroups, Group)
69+ , renderGroupByClause
70+ , HavingClause (NoHaving, Having)
71+ , renderHavingClause
72+ -- * Sorting
73+ , SortExpression (..)
74+ , renderSortExpression
8275 ) where
8376
8477import Control.DeepSeq
8578import Data.ByteString (ByteString)
86−import Data.Kind (Type)
79+import Data.Monoid hiding (All)
8780import Data.String
8881import Data.Word
8982import Generics.SOP hiding (from)
@@ -91,76 +84,25 @@ import GHC.TypeLits
9184
9285import qualified GHC.Generics as GHC
9386
94−import Squeal.PostgreSQL.Alias
9587import Squeal.PostgreSQL.Expression
96−import Squeal.PostgreSQL.Expression.Logic
97−import Squeal.PostgreSQL.Expression.Sort
98−import Squeal.PostgreSQL.Expression.Window
99−import Squeal.PostgreSQL.List
100−import Squeal.PostgreSQL.PG
10188import Squeal.PostgreSQL.Render
10289import Squeal.PostgreSQL.Schema
10390
104−-- $setup
105−-- >>> import Squeal.PostgreSQL
106−-- >>> import Data.Int (Int32, Int64)
107−-- >>> import Data.Monoid (Sum (..))
108−-- >>> import Data.Text (Text)
109−-- >>> import qualified Generics.SOP as SOP
110−
11191{- |
112−The process of retrieving or the command to retrieve data from
113−a database is called a `Query`.
114−
115−The general `Query` type is parameterized by
116−
117−* @outer :: FromType@ - outer scope for a correlated subquery,
118−* @commons :: FromType@ - scope for all `common` table expressions,
119−* @schemas :: SchemasType@ - scope for all `table`s and `view`s,
120−* @params :: [NullityType]@ - scope for all `Squeal.Expression.Parameter.parameter`s,
121−* @row :: RowType@ - return type of the `Query`.
122−-}
123−newtype Query
124− (outer :: FromType)
125− (commons :: FromType)
126− (schemas :: SchemasType)
127− (params :: [NullityType])
128− (row :: RowType)
129− = UnsafeQuery { renderQuery :: ByteString }
130− deriving (GHC.Generic,Show,Eq,Ord,NFData)
131−instance RenderSQL (Query outer commons schemas params row) where renderSQL = renderQuery
132−
133−{- |
134−The top level `Query_` type is parameterized by a @schemas@ `SchemasType`,
135−against which the query is type-checked, an input @parameters@ Haskell `Type`,
136−and an ouput row Haskell `Type`.
137−
138−A top-level query can be run
139−using `Squeal.PostgreSQL.PQ.runQueryParams`, or if @parameters = ()@
140−using `Squeal.PostgreSQL.PQ.runQuery`.
141−
142−Generally, @parameters@ will be a Haskell tuple or record whose entries
143−may be referenced using positional
144−`Squeal.PostgreSQL.Expression.Parameter.parameter`s and @row@ will be a
145−Haskell record, whose entries will be targeted using overloaded labels.
146−
147−Let's see some examples of queries.
148−
149−>>> :set -XDeriveAnyClass -XDerivingStrategies
150−>>> :{
151−data Row a b = Row { col1 :: a, col2 :: b }
152− deriving stock (GHC.Generic)
153− deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
154−:}
92+The process of retrieving or the command to retrieve data from a database
93+is called a `Query`. The `select`, `selectStar`, `selectDotStar`,
94+`selectDistinct`, `selectDistinctStar` and `selectDistinctDotStar` commands
95+are used to specify queries.
15596
15697simple query:
15798
158−>>> type Columns = '["col1" ::: 'NoDef :=> 'NotNull 'PGint4, "col2" ::: 'NoDef :=> 'NotNull 'PGint4]
159−>>> type Schema = '["tab" ::: 'Table ('[] :=> Columns)]
16099>>> :{
161100let
162− query :: Query_ (Public Schema) () (Row Int32 Int32)
163− query = select Star (from (table #tab))
101+ query :: Query
102+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
103+ '[]
104+ '["col" ::: 'Null 'PGint4]
105+ query = selectStar (from (table #tab))
164106in printSQL query
165107:}
166108SELECT * FROM "tab" AS "tab"
@@ -169,22 +111,34 @@ restricted query:
169111
170112>>> :{
171113let
172− query :: Query_ (Public Schema) () (Row Int32 Int32)
114+ query :: Query
115+ '[ "tab" ::: 'Table ('[] :=>
116+ '[ "col1" ::: 'NoDef :=> 'NotNull 'PGint4
117+ , "col2" ::: 'NoDef :=> 'NotNull 'PGint4 ])]
118+ '[]
119+ '[ "sum" ::: 'NotNull 'PGint4
120+ , "col1" ::: 'NotNull 'PGint4 ]
173121 query =
174− select_ ((#col1 + #col2) `as` #col1 :* #col1 `as` #col2)
122+ select
123+ ((#col1 + #col2) `as` #sum :* #col1)
175124 ( from (table #tab)
176125 & where_ (#col1 .> #col2)
177126 & where_ (#col2 .> 0) )
178127in printSQL query
179128:}
180−SELECT ("col1" + "col2") AS "col1", "col1" AS "col2" FROM "tab" AS "tab" WHERE (("col1" > "col2") AND ("col2" > 0))
129+SELECT ("col1" + "col2") AS "sum", "col1" AS "col1" FROM "tab" AS "tab" WHERE (("col1" > "col2") AND ("col2" > 0))
181130
182131subquery:
183132
184133>>> :{
185134let
186− query :: Query_ (Public Schema) () (Row Int32 Int32)
187− query = select Star (from (subquery (select Star (from (table #tab)) `as` #sub)))
135+ query :: Query
136+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
137+ '[]
138+ '["col" ::: 'Null 'PGint4]
139+ query =
140+ selectStar
141+ (from (subquery (selectStar (from (table #tab)) `as` #sub)))
188142in printSQL query
189143:}
190144SELECT * FROM (SELECT * FROM "tab" AS "tab") AS "sub"
@@ -193,8 +147,12 @@ limits and offsets:
193147
194148>>> :{
195149let
196− query :: Query_ (Public Schema) () (Row Int32 Int32)
197− query = select Star (from (table #tab) & limit 100 & offset 2 & limit 50 & offset 2)
150+ query :: Query
151+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
152+ '[]
153+ '["col" ::: 'Null 'PGint4]
154+ query = selectStar
155+ (from (table #tab) & limit 100 & offset 2 & limit 50 & offset 2)
198156in printSQL query
199157:}
200158SELECT * FROM "tab" AS "tab" LIMIT 50 OFFSET 4
@@ -203,80 +161,85 @@ parameterized query:
203161
204162>>> :{
205163let
206− query :: Query_ (Public Schema) (Only Int32) (Row Int32 Int32)
207− query = select Star (from (table #tab) & where_ (#col1 .> param @1))
164+ query :: Query
165+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'NotNull 'PGfloat8])]
166+ '[ 'NotNull 'PGfloat8]
167+ '["col" ::: 'NotNull 'PGfloat8]
168+ query = selectStar
169+ (from (table #tab) & where_ (#col .> param @1))
208170in printSQL query
209171:}
210−SELECT * FROM "tab" AS "tab" WHERE ("col1" > ($1 :: int4))
172+SELECT * FROM "tab" AS "tab" WHERE ("col" > ($1 :: float8))
211173
212174aggregation query:
213175
214176>>> :{
215177let
216− query :: Query_ (Public Schema) () (Row Int64 Int32)
178+ query :: Query
179+ '[ "tab" ::: 'Table ('[] :=>
180+ '[ "col1" ::: 'NoDef :=> 'NotNull 'PGint4
181+ , "col2" ::: 'NoDef :=> 'NotNull 'PGint4 ])]
182+ '[]
183+ '[ "sum" ::: 'NotNull 'PGint4
184+ , "col1" ::: 'NotNull 'PGint4 ]
217185 query =
218− select_ ((fromNull 0 (sum_ (All #col2))) `as` #col1 :* #col1 `as` #col2)
186+ select (sum_ #col2 `as` #sum :* #col1)
219187 ( from (table (#tab `as` #table1))
220188 & groupBy #col1
221− & having (sum_ (Distinct #col2) .> 1) )
189+ & having (#col1 + sum_ #col2 .> 1) )
222190in printSQL query
223191:}
224−SELECT COALESCE(sum(ALL "col2"), 0) AS "col1", "col1" AS "col2" FROM "tab" AS "table1" GROUP BY "col1" HAVING (sum(DISTINCT "col2") > 1)
192+SELECT sum("col2") AS "sum", "col1" AS "col1" FROM "tab" AS "table1" GROUP BY "col1" HAVING (("col1" + sum("col2")) > 1)
225193
226194sorted query:
227195
228196>>> :{
229197let
230− query :: Query_ (Public Schema) () (Row Int32 Int32)
231− query = select Star (from (table #tab) & orderBy [#col1 & Asc])
198+ query :: Query
199+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
200+ '[]
201+ '["col" ::: 'Null 'PGint4]
202+ query = selectStar
203+ (from (table #tab) & orderBy [#col & AscNullsFirst])
232204in printSQL query
233205:}
234−SELECT * FROM "tab" AS "tab" ORDER BY "col1" ASC
206+SELECT * FROM "tab" AS "tab" ORDER BY "col" ASC NULLS FIRST
235207
236208joins:
237209
238−>>> :{
239−type OrdersColumns =
240− '[ "id" ::: 'NoDef :=> 'NotNull 'PGint4
241− , "price" ::: 'NoDef :=> 'NotNull 'PGfloat4
242− , "customer_id" ::: 'NoDef :=> 'NotNull 'PGint4
243− , "shipper_id" ::: 'NoDef :=> 'NotNull 'PGint4 ]
244−:}
245−
246−>>> :{
247−type OrdersConstraints =
248− '["pk_orders" ::: PrimaryKey '["id"]
249− ,"fk_customers" ::: ForeignKey '["customer_id"] "customers" '["id"]
250− ,"fk_shippers" ::: ForeignKey '["shipper_id"] "shippers" '["id"] ]
251−:}
252−
253−>>> type NamesColumns = '["id" ::: 'NoDef :=> 'NotNull 'PGint4, "name" ::: 'NoDef :=> 'NotNull 'PGtext]
254−>>> type CustomersConstraints = '["pk_customers" ::: PrimaryKey '["id"]]
255−>>> type ShippersConstraints = '["pk_shippers" ::: PrimaryKey '["id"]]
256−>>> :{
257−type OrdersSchema =
258− '[ "orders" ::: 'Table (OrdersConstraints :=> OrdersColumns)
259− , "customers" ::: 'Table (CustomersConstraints :=> NamesColumns)
260− , "shippers" ::: 'Table (ShippersConstraints :=> NamesColumns) ]
261−:}
262−
263−>>> :{
264−data Order = Order
265− { price :: Float
266− , customerName :: Text
267− , shipperName :: Text
268− } deriving GHC.Generic
269−instance SOP.Generic Order
270−instance SOP.HasDatatypeInfo Order
271−:}
272−
210+>>> :set -XFlexibleContexts
273211>>> :{
274212let
275− query :: Query_ (Public OrdersSchema) () Order
276− query = select_
277− ( #o ! #price `as` #price :*
278− #c ! #name `as` #customerName :*
279− #s ! #name `as` #shipperName )
213+ query :: Query
214+ '[ "orders" ::: 'Table (
215+ '["pk_orders" ::: PrimaryKey '["id"]
216+ ,"fk_customers" ::: ForeignKey '["customer_id"] "customers" '["id"]
217+ ,"fk_shippers" ::: ForeignKey '["shipper_id"] "shippers" '["id"]] :=>
218+ '[ "id" ::: 'NoDef :=> 'NotNull 'PGint4
219+ , "price" ::: 'NoDef :=> 'NotNull 'PGfloat4
220+ , "customer_id" ::: 'NoDef :=> 'NotNull 'PGint4
221+ , "shipper_id" ::: 'NoDef :=> 'NotNull 'PGint4
222+ ])
223+ , "customers" ::: 'Table (
224+ '["pk_customers" ::: PrimaryKey '["id"]] :=>
225+ '[ "id" ::: 'NoDef :=> 'NotNull 'PGint4
226+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
227+ ])
228+ , "shippers" ::: 'Table (
229+ '["pk_shippers" ::: PrimaryKey '["id"]] :=>
230+ '[ "id" ::: 'NoDef :=> 'NotNull 'PGint4
231+ , "name" ::: 'NoDef :=> 'NotNull 'PGtext
232+ ])
233+ ]
234+ '[]
235+ '[ "order_price" ::: 'NotNull 'PGfloat4
236+ , "customer_name" ::: 'NotNull 'PGtext
237+ , "shipper_name" ::: 'NotNull 'PGtext
238+ ]
239+ query = select
240+ ( #o ! #price `as` #order_price :*
241+ #c ! #name `as` #customer_name :*
242+ #s ! #name `as` #shipper_name )
280243 ( from (table (#orders `as` #o)
281244 & innerJoin (table (#customers `as` #c))
282245 (#o ! #customer_id .== #c ! #id)
@@ -284,345 +247,190 @@ let
284247 (#o ! #shipper_id .== #s ! #id)) )
285248in printSQL query
286249:}
287−SELECT "o"."price" AS "price", "c"."name" AS "customerName", "s"."name" AS "shipperName" FROM "orders" AS "o" INNER JOIN "customers" AS "c" ON ("o"."customer_id" = "c"."id") INNER JOIN "shippers" AS "s" ON ("o"."shipper_id" = "s"."id")
250+SELECT "o"."price" AS "order_price", "c"."name" AS "customer_name", "s"."name" AS "shipper_name" FROM "orders" AS "o" INNER JOIN "customers" AS "c" ON ("o"."customer_id" = "c"."id") INNER JOIN "shippers" AS "s" ON ("o"."shipper_id" = "s"."id")
288251
289252self-join:
290253
291254>>> :{
292255let
293− query :: Query_ (Public Schema) () (Row Int32 Int32)
294− query = select
295− (#t1 & DotStar)
256+ query :: Query
257+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
258+ '[]
259+ '["col" ::: 'Null 'PGint4]
260+ query = selectDotStar #t1
296261 (from (table (#tab `as` #t1) & crossJoin (table (#tab `as` #t2))))
297262in printSQL query
298263:}
299264SELECT "t1".* FROM "tab" AS "t1" CROSS JOIN "tab" AS "t2"
300265
301−value queries:
302−
303−>>> :{
304−let
305− query :: Query_ schemas () (Row String Bool)
306− query = values
307− ("true" `as` #col1 :* true `as` #col2)
308− ["false" `as` #col1 :* false `as` #col2]
309−in printSQL query
310−:}
311−SELECT * FROM (VALUES (E'true', TRUE), (E'false', FALSE)) AS t ("col1", "col2")
312−
313266set operations:
314267
315268>>> :{
316269let
317− query :: Query_ (Public Schema) () (Row Int32 Int32)
318− query = select Star (from (table #tab)) `unionAll` select Star (from (table #tab))
319−in printSQL query
320−:}
321−(SELECT * FROM "tab" AS "tab") UNION ALL (SELECT * FROM "tab" AS "tab")
322−
323−with queries:
324−
325−>>> :{
326−let
327− query :: Query_ (Public Schema) () (Row Int32 Int32)
328− query = with (
329− select Star (from (table #tab)) `as` #cte1 :>>
330− select Star (from (common #cte1)) `as` #cte2
331− ) (select Star (from (common #cte2)))
332−in printSQL query
333−:}
334−WITH "cte1" AS (SELECT * FROM "tab" AS "tab"), "cte2" AS (SELECT * FROM "cte1" AS "cte1") SELECT * FROM "cte2" AS "cte2"
335−
336−window function queries
337−
338−>>> :{
339−let
340− query :: Query_ (Public Schema) () (Row Int32 Int64)
341− query = select
342− (#col1 & Also (rank `as` #col2 `Over` (partitionBy #col1 & orderBy [#col2 & Asc])))
343− (from (table #tab))
344−in printSQL query
345−:}
346−SELECT "col1" AS "col1", rank() OVER (PARTITION BY "col1" ORDER BY "col2" ASC) AS "col2" FROM "tab" AS "tab"
347−
348−correlated subqueries
349−
350−>>> :{
351−let
352− query :: Query_ (Public Schema) () (Only Int32)
270+ query :: Query
271+ '["tab" ::: 'Table ('[] :=> '["col" ::: 'NoDef :=> 'Null 'PGint4])]
272+ '[]
273+ '["col" ::: 'Null 'PGint4]
353274 query =
354− select (#col1 `as` #fromOnly) (from (table (#tab `as` #t1))
355− & where_ (exists (
356− select Star (from (table (#tab `as` #t2))
357− & where_ (#t2 ! #col2 .== #t1 ! #col1)))))
275+ selectStar (from (table #tab))
276+ `unionAll`
277+ selectStar (from (table #tab))
358278in printSQL query
359279:}
360−SELECT "col1" AS "fromOnly" FROM "tab" AS "t1" WHERE EXISTS (SELECT * FROM "tab" AS "t2" WHERE ("t2"."col2" = "t1"."col1"))
361−
280+(SELECT * FROM "tab" AS "tab") UNION ALL (SELECT * FROM "tab" AS "tab")
362281-}
363−type family Query_
364− (schemas :: SchemasType)
365− (parameters :: Type)
366− (row :: Type) where
367− Query_ schemas params row =
368− Query '[] '[] schemas (TuplePG params) (RowPG row)
282+newtype Query
283+ (schema :: SchemaType)
284+ (params :: [NullityType])
285+ (columns :: RelationType)
286+ = UnsafeQuery { renderQuery :: ByteString }
287+ deriving (GHC.Generic,Show,Eq,Ord,NFData)
288+instance RenderSQL (Query schema params columns) where renderSQL = renderQuery
369289
370290-- | The results of two queries can be combined using the set operation
371291-- `union`. Duplicate rows are eliminated.
372292union
373− :: Query outer commons schemas params columns
374− -> Query outer commons schemas params columns
375− -> Query outer commons schemas params columns
293+ :: Query schema params columns
294+ -> Query schema params columns
295+ -> Query schema params columns
376296q1 `union` q2 = UnsafeQuery $
377− parenthesized (renderSQL q1)
297+ parenthesized (renderQuery q1)
378298 <+> "UNION"
379− <+> parenthesized (renderSQL q2)
299+ <+> parenthesized (renderQuery q2)
380300
381301-- | The results of two queries can be combined using the set operation
382302-- `unionAll`, the disjoint union. Duplicate rows are retained.
383303unionAll
384− :: Query outer commons schemas params columns
385− -> Query outer commons schemas params columns
386− -> Query outer commons schemas params columns
304+ :: Query schema params columns
305+ -> Query schema params columns
306+ -> Query schema params columns
387307q1 `unionAll` q2 = UnsafeQuery $
388− parenthesized (renderSQL q1)
308+ parenthesized (renderQuery q1)
389309 <+> "UNION" <+> "ALL"
390− <+> parenthesized (renderSQL q2)
310+ <+> parenthesized (renderQuery q2)
391311
392312-- | The results of two queries can be combined using the set operation
393313-- `intersect`, the intersection. Duplicate rows are eliminated.
394314intersect
395− :: Query outer commons schemas params columns
396− -> Query outer commons schemas params columns
397− -> Query outer commons schemas params columns
315+ :: Query schema params columns
316+ -> Query schema params columns
317+ -> Query schema params columns
398318q1 `intersect` q2 = UnsafeQuery $
399− parenthesized (renderSQL q1)
319+ parenthesized (renderQuery q1)
400320 <+> "INTERSECT"
401− <+> parenthesized (renderSQL q2)
321+ <+> parenthesized (renderQuery q2)
402322
403323-- | The results of two queries can be combined using the set operation
404324-- `intersectAll`, the intersection. Duplicate rows are retained.
405325intersectAll
406− :: Query outer commons schemas params columns
407− -> Query outer commons schemas params columns
408− -> Query outer commons schemas params columns
326+ :: Query schema params columns
327+ -> Query schema params columns
328+ -> Query schema params columns
409329q1 `intersectAll` q2 = UnsafeQuery $
410− parenthesized (renderSQL q1)
330+ parenthesized (renderQuery q1)
411331 <+> "INTERSECT" <+> "ALL"
412− <+> parenthesized (renderSQL q2)
332+ <+> parenthesized (renderQuery q2)
413333
414334-- | The results of two queries can be combined using the set operation
415335-- `except`, the set difference. Duplicate rows are eliminated.
416336except
417− :: Query outer commons schemas params columns
418− -> Query outer commons schemas params columns
419− -> Query outer commons schemas params columns
337+ :: Query schema params columns
338+ -> Query schema params columns
339+ -> Query schema params columns
420340q1 `except` q2 = UnsafeQuery $
421− parenthesized (renderSQL q1)
341+ parenthesized (renderQuery q1)
422342 <+> "EXCEPT"
423− <+> parenthesized (renderSQL q2)
343+ <+> parenthesized (renderQuery q2)
424344
425345-- | The results of two queries can be combined using the set operation
426346-- `exceptAll`, the set difference. Duplicate rows are retained.
427347exceptAll
428− :: Query outer commons schemas params columns
429− -> Query outer commons schemas params columns
430− -> Query outer commons schemas params columns
348+ :: Query schema params columns
349+ -> Query schema params columns
350+ -> Query schema params columns
431351q1 `exceptAll` q2 = UnsafeQuery $
432− parenthesized (renderSQL q1)
352+ parenthesized (renderQuery q1)
433353 <+> "EXCEPT" <+> "ALL"
434− <+> parenthesized (renderSQL q2)
354+ <+> parenthesized (renderQuery q2)
435355
436356{-----------------------------------------
437357SELECT queries
438358-----------------------------------------}
439359
440−{- | The simplest kinds of `Selection` are `Star` and `DotStar` which
441−emits all columns that a `TableExpression` produces. A select `List`
442−is a list of `Expression`s. A `Selection` could be a list of
443−`WindowFunction`s `Over` `WindowDefinition`. `Additional` `Selection`s can
444−be selected with `Also`.
445−-}
446−data Selection outer commons grp schemas params from row where
447− Star
448− :: HasUnique tab from row
449− => Selection outer commons 'Ungrouped schemas params from row
450− -- ^ `HasUnique` table in the `FromClause`
451− DotStar
452− :: Has tab from row
453− => Alias tab
454− -- ^ `Has` table with `Alias`
455− -> Selection outer commons 'Ungrouped schemas params from row
456− List
457− :: SListI row
458− => NP (Aliased (Expression outer commons grp schemas params from)) row
459− -- ^ `NP` list of `Aliased` `Expression`s
460− -> Selection outer commons grp schemas params from row
461− Over
462− :: SListI row
463− => NP (Aliased (WindowFunction outer commons grp schemas params from)) row
464− -- ^ `NP` list of `Aliased` `WindowFunction`s
465− -> WindowDefinition outer commons grp schemas params from
466− -> Selection outer commons grp schemas params from row
467− Also
468− :: Selection outer commons grp schemas params from right
469− -- ^ `Additional` `Selection`
470− -> Selection outer commons grp schemas params from left
471− -> Selection outer commons grp schemas params from (Join left right)
472−instance Additional (Selection outer commons grp schemas params from) where
473− also = Also
474−instance (KnownSymbol col, row ~ '[col ::: ty])
475− => Aliasable col
476− (Expression outer commons grp schemas params from ty)
477− (Selection outer commons grp schemas params from row) where
478− expr `as` col = List (expr `as` col)
479−instance (Has tab (Join outer from) row0, Has col row0 ty, row1 ~ '[col ::: ty])
480− => IsQualified tab col
481− (Selection outer commons 'Ungrouped schemas params from row1) where
482− tab ! col = tab ! col `as` col
483−instance
484− ( Has tab (Join outer from) row0
485− , Has col row0 ty
486− , row1 ~ '[col ::: ty]
487− , GroupedBy tab col bys )
488− => IsQualified tab col
489− (Selection outer commons ('Grouped bys) schemas params from row1) where
490− tab ! col = tab ! col `as` col
491−instance (HasUnique tab (Join outer from) row0, Has col row0 ty, row1 ~ '[col ::: ty])
492− => IsLabel col
493− (Selection outer commons 'Ungrouped schemas params from row1) where
494− fromLabel = fromLabel @col `as` Alias
495−instance
496− ( HasUnique tab (Join outer from) row0
497− , Has col row0 ty
498− , row1 ~ '[col ::: ty]
499− , GroupedBy tab col bys )
500− => IsLabel col
501− (Selection outer commons ('Grouped bys) schemas params from row1) where
502− fromLabel = fromLabel @col `as` Alias
503−
504−instance RenderSQL (Selection outer commons grp schemas params from row) where
505− renderSQL = \case
506− List list -> renderCommaSeparated (renderAliased renderSQL) list
507− Star -> "*"
508− DotStar tab -> renderSQL tab <> ".*"
509− Also right left -> renderSQL left <> ", " <> renderSQL right
510− Over winFns winDef ->
511− let
512− renderOver
513− :: Aliased (WindowFunction outer commons grp schemas params from) field
514− -> ByteString
515− renderOver (winFn `As` col) = renderSQL winFn
516− <+> "OVER" <+> parenthesized (renderSQL winDef)
517− <+> "AS" <+> renderSQL col
518− in
519− renderCommaSeparated renderOver winFns
520−
521−instance IsString
522− (Selection outer commons grp schemas params from '["fromOnly" ::: 'NotNull 'PGtext]) where
523− fromString str = fromString str `as` Alias
524−
525360-- | the `TableExpression` in the `select` command constructs an intermediate
526361-- virtual table by possibly combining tables, views, eliminating rows,
527362-- grouping, etc. This table is finally passed on to processing by
528−-- the select list. The `Selection` determines which columns of
363+-- the select list. The select list determines which columns of
529364-- the intermediate table are actually output.
530365select
531− :: (SListI row, row ~ (x ': xs))
532− => Selection outer commons grp schemas params from row
533− -- ^ selection
534− -> TableExpression outer commons grp schemas params from
535− -- ^ intermediate virtual table
536− -> Query outer commons schemas params row
537−select selection tabexpr = UnsafeQuery $
538− "SELECT"
539− <+> renderSQL selection
540− <+> renderSQL tabexpr
541−
542−-- | Like `select` but takes an `NP` list of `Expression`s instead
543−-- of a general `Selection`.
544−select_
545− :: (SListI row, row ~ (x ': xs))
546− => NP (Aliased (Expression outer commons grp schemas params from)) row
366+ :: SListI columns
367+ => NP (Aliased (Expression schema relations grouping params)) (column ': columns)
547368 -- ^ select list
548− -> TableExpression outer commons grp schemas params from
369+ -> TableExpression schema params relations grouping
549370 -- ^ intermediate virtual table
550− -> Query outer commons schemas params row
551−select_ = select . List
371+ -> Query schema params (column ': columns)
372+select list rels = UnsafeQuery $
373+ "SELECT"
374+ <+> renderCommaSeparated (renderAliasedAs renderExpression) list
375+ <+> renderTableExpression rels
552376
553377-- | After the select list has been processed, the result table can
554378-- be subject to the elimination of duplicate rows using `selectDistinct`.
555379selectDistinct
556− :: (SListI columns, columns ~ (col ': cols))
557− => Selection outer commons grp schemas params from columns
558− -- ^ selection
559− -> TableExpression outer commons grp schemas params from
380+ :: SListI columns
381+ => NP (Aliased (Expression schema relations 'Ungrouped params)) (column ': columns)
382+ -- ^ select list
383+ -> TableExpression schema params relations 'Ungrouped
560384 -- ^ intermediate virtual table
561− -> Query outer commons schemas params columns
562−selectDistinct selection tabexpr = UnsafeQuery $
385+ -> Query schema params (column ': columns)
386+selectDistinct list rels = UnsafeQuery $
563387 "SELECT DISTINCT"
564− <+> renderSQL selection
565− <+> renderSQL tabexpr
566−
567−-- | Like `selectDistinct` but takes an `NP` list of `Expression`s instead
568−-- of a general `Selection`.
569−selectDistinct_
570− :: (SListI columns, columns ~ (col ': cols))
571− => NP (Aliased (Expression outer commons grp schemas params from)) columns
572− -- ^ select list
573− -> TableExpression outer commons grp schemas params from
388+ <+> renderCommaSeparated (renderAliasedAs renderExpression) list
389+ <+> renderTableExpression rels
390+
391+-- | The simplest kind of query is `selectStar` which emits all columns
392+-- that the table expression produces.
393+selectStar
394+ :: HasUnique relation relations columns
395+ => TableExpression schema params relations 'Ungrouped
574396 -- ^ intermediate virtual table
575− -> Query outer commons schemas params columns
576−selectDistinct_ = selectDistinct . List
577−
578−{-|
579−`selectDistinctOn` keeps only the first row of each set of rows where
580−the given expressions evaluate to equal. The DISTINCT ON expressions are
581−interpreted using the same rules as for ORDER BY. ORDER BY is used to
582−ensure that the desired row appears first.
583−
584−The DISTINCT ON expression(s) must match the leftmost ORDER BY expression(s).
585−The ORDER BY clause will normally contain additional expression(s) that
586−determine the desired precedence of rows within each DISTINCT ON group.
587−
588−In order to guarantee they match and reduce redundancy, this function
589−will prepend the The DISTINCT ON expressions to the ORDER BY clause.
590−-}
591−selectDistinctOn
592− :: (SListI columns, columns ~ (col ': cols))
593− => [SortExpression outer commons grp schemas params from]
594− -- ^ DISTINCT ON expression(s) and prepended to ORDER BY clause
595− -> Selection outer commons grp schemas params from columns
596− -- ^ selection
597− -> TableExpression outer commons grp schemas params from
397+ -> Query schema params columns
398+selectStar rels = UnsafeQuery $ "SELECT" <+> "*" <+> renderTableExpression rels
399+
400+-- | A `selectDistinctStar` emits all columns that the table expression
401+-- produces and eliminates duplicate rows.
402+selectDistinctStar
403+ :: HasUnique relation relations columns
404+ => TableExpression schema params relations 'Ungrouped
598405 -- ^ intermediate virtual table
599− -> Query outer commons schemas params columns
600−selectDistinctOn distincts selection tab = UnsafeQuery $
601− "SELECT DISTINCT ON"
602− <+> parenthesized (commaSeparated (renderDistinctOn <$> distincts))
603− <+> renderSQL selection
604− <+> renderSQL (tab {orderByClause = distincts <> orderByClause tab})
605− where
606− renderDistinctOn = \case
607− Asc expression -> renderSQL expression
608− Desc expression -> renderSQL expression
609− AscNullsFirst expression -> renderSQL expression
610− DescNullsFirst expression -> renderSQL expression
611− AscNullsLast expression -> renderSQL expression
612− DescNullsLast expression -> renderSQL expression
613−
614−-- | Like `selectDistinctOn` but takes an `NP` list of `Expression`s instead
615−-- of a general `Selection`.
616−selectDistinctOn_
617− :: (SListI columns, columns ~ (col ': cols))
618− => [SortExpression outer commons grp schemas params from]
619− -- ^ distinct on and return the first row in ordering
620− -> NP (Aliased (Expression outer commons grp schemas params from)) columns
621− -- ^ selection
622− -> TableExpression outer commons grp schemas params from
406+ -> Query schema params columns
407+selectDistinctStar rels = UnsafeQuery $
408+ "SELECT DISTINCT" <+> "*" <+> renderTableExpression rels
409+
410+-- | When working with multiple tables, it can also be useful to ask
411+-- for all the columns of a particular table, using `selectDotStar`.
412+selectDotStar
413+ :: Has relation relations columns
414+ => Alias relation
415+ -- ^ particular virtual subtable
416+ -> TableExpression schema params relations 'Ungrouped
623417 -- ^ intermediate virtual table
624− -> Query outer commons schemas params columns
625−selectDistinctOn_ distincts = selectDistinctOn distincts . List
418+ -> Query schema params columns
419+selectDotStar rel relations = UnsafeQuery $
420+ "SELECT" <+> renderAlias rel <> ".*" <+> renderTableExpression relations
421+
422+-- | A `selectDistinctDotStar` asks for all the columns of a particular table,
423+-- and eliminates duplicate rows.
424+selectDistinctDotStar
425+ :: Has relation relations columns
426+ => Alias relation
427+ -- ^ particular virtual table
428+ -> TableExpression schema params relations 'Ungrouped
429+ -- ^ intermediate virtual table
430+ -> Query schema params columns
431+selectDistinctDotStar rel relations = UnsafeQuery $
432+ "SELECT DISTINCT" <+> renderAlias rel <> ".*"
433+ <+> renderTableExpression relations
626434
627435-- | `values` computes a row value or set of row values
628436-- specified by value expressions. It is most commonly used
@@ -630,16 +438,16 @@ selectDistinctOn_ distincts = selectDistinctOn distincts . List
630438-- but it can be used on its own.
631439--
632440-- >>> type Row = '["a" ::: 'NotNull 'PGint4, "b" ::: 'NotNull 'PGtext]
633−-- >>> let query = values (1 `as` #a :* "one" `as` #b) [] :: Query outer commons schemas '[] Row
441+-- >>> let query = values (1 `as` #a :* "one" `as` #b) [] :: Query '[] '[] Row
634442-- >>> printSQL query
635443-- SELECT * FROM (VALUES (1, E'one')) AS t ("a", "b")
636444values
637445 :: SListI cols
638− => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
639− -> [NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols]
446+ => NP (Aliased (Expression schema '[] 'Ungrouped params)) cols
447+ -> [NP (Aliased (Expression schema '[] 'Ungrouped params)) cols]
640448 -- ^ When more than one row is specified, all the rows must
641449 -- must have the same number of elements
642− -> Query outer commons schemas params cols
450+ -> Query schema params cols
643451values rw rws = UnsafeQuery $ "SELECT * FROM"
644452 <+> parenthesized (
645453 "VALUES"
@@ -650,17 +458,17 @@ values rw rws = UnsafeQuery $ "SELECT * FROM"
650458 <+> parenthesized (renderCommaSeparated renderAliasPart rw)
651459 where
652460 renderAliasPart, renderValuePart
653− :: Aliased (Expression outer commons 'Ungrouped schemas params '[] ) ty -> ByteString
654− renderAliasPart (_ `As` name) = renderSQL name
655− renderValuePart (value `As` _) = renderSQL value
461+ :: Aliased (Expression schema '[] 'Ungrouped params) ty -> ByteString
462+ renderAliasPart (_ `As` name) = renderAlias name
463+ renderValuePart (value `As` _) = renderExpression value
656464
657465-- | `values_` computes a row value or set of row values
658466-- specified by value expressions.
659467values_
660468 :: SListI cols
661− => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
469+ => NP (Aliased (Expression schema '[] 'Ungrouped params)) cols
662470 -- ^ one row of values
663− -> Query outer commons schemas params cols
471+ -> Query schema params cols
664472values_ rw = values rw []
665473
666474{-----------------------------------------
@@ -674,17 +482,15 @@ Table Expressions
674482-- to a table on disk, a so-called base table, but more complex expressions
675483-- can be used to modify or combine base tables in various ways.
676484data TableExpression
677− (outer :: FromType)
678− (commons :: FromType)
679− (grp :: Grouping)
680− (schemas :: SchemasType)
485+ (schema :: SchemaType)
681486 (params :: [NullityType])
682− (from :: FromType)
487+ (relations :: RelationsType)
488+ (grouping :: Grouping)
683489 = TableExpression
684− { fromClause :: FromClause outer commons schemas params from
490+ { fromClause :: FromClause schema params relations
685491 -- ^ A table reference that can be a table name, or a derived table such
686492 -- as a subquery, a @JOIN@ construct, or complex combinations of these.
687− , whereClause :: [Condition outer commons 'Ungrouped schemas params from]
493+ , whereClause :: [Condition schema relations 'Ungrouped params]
688494 -- ^ optional search coditions, combined with `.&&`. After the processing
689495 -- of the `fromClause` is done, each row of the derived virtual table
690496 -- is checked against the search condition. If the result of the
@@ -693,20 +499,20 @@ data TableExpression
693499 -- at least one column of the table generated in the `fromClause`;
694500 -- this is not required, but otherwise the WHERE clause will
695501 -- be fairly useless.
696− , groupByClause :: GroupByClause grp from
502+ , groupByClause :: GroupByClause relations grouping
697503 -- ^ The `groupByClause` is used to group together those rows in a table
698504 -- that have the same values in all the columns listed. The order in which
699505 -- the columns are listed does not matter. The effect is to combine each
700506 -- set of rows having common values into one group row that represents all
701507 -- rows in the group. This is done to eliminate redundancy in the output
702508 -- and/or compute aggregates that apply to these groups.
703− , havingClause :: HavingClause outer commons grp schemas params from
509+ , havingClause :: HavingClause schema relations grouping params
704510 -- ^ If a table has been grouped using `groupBy`, but only certain groups
705511 -- are of interest, the `havingClause` can be used, much like a
706512 -- `whereClause`, to eliminate groups from the result. Expressions in the
707513 -- `havingClause` can refer both to grouped expressions and to ungrouped
708514 -- expressions (which necessarily involve an aggregate function).
709− , orderByClause :: [SortExpression outer commons grp schemas params from]
515+ , orderByClause :: [SortExpression schema relations grouping params]
710516 -- ^ The `orderByClause` is for optional sorting. When more than one
711517 -- `SortExpression` is specified, the later (right) values are used to sort
712518 -- rows that are equal according to the earlier (left) values.
@@ -716,69 +522,72 @@ data TableExpression
716522 -- will be returned (but possibly fewer, if the query itself yields
717523 -- fewer rows).
718524 , offsetClause :: [Word64]
719− -- ^ The `offsetClause` is combined with `Prelude.+` to give an offset count
525+ -- ^ The `offsetClause` is combined with `+` to give an offset count
720526 -- if nonempty. The offset count says to skip that many rows before
721527 -- beginning to return rows. The rows are skipped before the limit count
722528 -- is applied.
723− } deriving (GHC.Generic)
529+ }
724530
725531-- | Render a `TableExpression`
726−instance RenderSQL (TableExpression outer commons grp schemas params from) where
727− renderSQL
728− (TableExpression frm' whs' grps' hvs' srts' lims' offs') = mconcat
729− [ "FROM ", renderSQL frm'
730− , renderWheres whs'
731− , renderSQL grps'
732− , renderSQL hvs'
733− , renderOrderByClause srts'
734− , renderLimits lims'
735− , renderOffsets offs' ]
736− where
737− renderWheres = \case
738− [] -> ""
739− wh:[] -> " WHERE" <+> renderSQL wh
740− wh:whs -> " WHERE" <+> renderSQL (foldr (.&&) wh whs)
741− renderOrderByClause = \case
742− [] -> ""
743− srts -> " ORDER BY"
744− <+> commaSeparated (renderSQL <$> srts)
745− renderLimits = \case
746− [] -> ""
747− lims -> " LIMIT" <+> fromString (show (minimum lims))
748− renderOffsets = \case
749− [] -> ""
750− offs -> " OFFSET" <+> fromString (show (sum offs))
532+renderTableExpression
533+ :: TableExpression schema params relations grouping
534+ -> ByteString
535+renderTableExpression
536+ (TableExpression frm' whs' grps' hvs' srts' lims' offs') = mconcat
537+ [ "FROM ", renderFromClause frm'
538+ , renderWheres whs'
539+ , renderGroupByClause grps'
540+ , renderHavingClause hvs'
541+ , renderOrderByClause srts'
542+ , renderLimits lims'
543+ , renderOffsets offs'
544+ ]
545+ where
546+ renderWheres = \case
547+ [] -> ""
548+ wh:[] -> " WHERE" <+> renderExpression wh
549+ wh:whs -> " WHERE" <+> renderExpression (foldr (.&&) wh whs)
550+ renderOrderByClause = \case
551+ [] -> ""
552+ srts -> " ORDER BY"
553+ <+> commaSeparated (renderSortExpression <$> srts)
554+ renderLimits = \case
555+ [] -> ""
556+ lims -> " LIMIT" <+> fromString (show (minimum lims))
557+ renderOffsets = \case
558+ [] -> ""
559+ offs -> " OFFSET" <+> fromString (show (sum offs))
751560
752561-- | A `from` generates a `TableExpression` from a table reference that can be
753562-- a table name, or a derived table such as a subquery, a JOIN construct,
754563-- or complex combinations of these. A `from` may be transformed by `where_`,
755−-- `groupBy`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
564+-- `group`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
756565-- to match the left-to-right sequencing of their placement in SQL.
757566from
758− :: FromClause outer commons schemas params from -- ^ table reference
759− -> TableExpression outer commons 'Ungrouped schemas params from
760−from tab = TableExpression tab [] noGroups NoHaving [] [] []
567+ :: FromClause schema params relations -- ^ table reference
568+ -> TableExpression schema params relations 'Ungrouped
569+from rels = TableExpression rels [] NoGroups NoHaving [] [] []
761570
762571-- | A `where_` is an endomorphism of `TableExpression`s which adds a
763572-- search condition to the `whereClause`.
764573where_
765− :: Condition outer commons 'Ungrouped schemas params from -- ^ filtering condition
766− -> TableExpression outer commons grp schemas params from
767− -> TableExpression outer commons grp schemas params from
574+ :: Condition schema relations 'Ungrouped params -- ^ filtering condition
575+ -> TableExpression schema params relations grouping
576+ -> TableExpression schema params relations grouping
768577where_ wh rels = rels {whereClause = wh : whereClause rels}
769578
770579-- | A `groupBy` is a transformation of `TableExpression`s which switches
771−-- its `Grouping` from `Ungrouped` to `Grouped`. Use @groupBy Nil@ to perform
580+-- its `Grouping` from `Ungrouped` to `Grouped`. Use @group Nil@ to perform
772581-- a "grand total" aggregation query.
773582groupBy
774583 :: SListI bys
775− => NP (By from) bys -- ^ grouped columns
776− -> TableExpression outer commons 'Ungrouped schemas params from
777− -> TableExpression outer commons ('Grouped bys) schemas params from
584+ => NP (By relations) bys -- ^ grouped columns
585+ -> TableExpression schema params relations 'Ungrouped
586+ -> TableExpression schema params relations ('Grouped bys)
778587groupBy bys rels = TableExpression
779588 { fromClause = fromClause rels
780589 , whereClause = whereClause rels
781− , groupByClause = group bys
590+ , groupByClause = Group bys
782591 , havingClause = Having []
783592 , orderByClause = []
784593 , limitClause = limitClause rels
@@ -788,29 +597,34 @@ groupBy bys rels = TableExpression
788597-- | A `having` is an endomorphism of `TableExpression`s which adds a
789598-- search condition to the `havingClause`.
790599having
791− :: Condition outer commons ('Grouped bys) schemas params from -- ^ having condition
792− -> TableExpression outer commons ('Grouped bys) schemas params from
793− -> TableExpression outer commons ('Grouped bys) schemas params from
600+ :: Condition schema relations ('Grouped bys) params -- ^ having condition
601+ -> TableExpression schema params relations ('Grouped bys)
602+ -> TableExpression schema params relations ('Grouped bys)
794603having hv rels = rels
795604 { havingClause = case havingClause rels of Having hvs -> Having (hv:hvs) }
796605
797−instance OrderBy TableExpression where
798− orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}
606+-- | An `orderBy` is an endomorphism of `TableExpression`s which appends an
607+-- ordering to the right of the `orderByClause`.
608+orderBy
609+ :: [SortExpression schema relations grouping params] -- ^ sort expressions
610+ -> TableExpression schema params relations grouping
611+ -> TableExpression schema params relations grouping
612+orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}
799613
800614-- | A `limit` is an endomorphism of `TableExpression`s which adds to the
801615-- `limitClause`.
802616limit
803617 :: Word64 -- ^ limit parameter
804− -> TableExpression outer commons grp schemas params from
805− -> TableExpression outer commons grp schemas params from
618+ -> TableExpression schema params relations grouping
619+ -> TableExpression schema params relations grouping
806620limit lim rels = rels {limitClause = lim : limitClause rels}
807621
808622-- | An `offset` is an endomorphism of `TableExpression`s which adds to the
809623-- `offsetClause`.
810624offset
811625 :: Word64 -- ^ offset parameter
812− -> TableExpression outer commons grp schemas params from
813− -> TableExpression outer commons grp schemas params from
626+ -> TableExpression schema params relations grouping
627+ -> TableExpression schema params relations grouping
814628offset off rels = rels {offsetClause = off : offsetClause rels}
815629
816630{-----------------------------------------
@@ -821,76 +635,61 @@ FROM clauses
821635A `FromClause` can be a table name, or a derived table such
822636as a subquery, a @JOIN@ construct, or complex combinations of these.
823637-}
824−newtype FromClause outer commons schemas params from
638+newtype FromClause schema params relations
825639 = UnsafeFromClause { renderFromClause :: ByteString }
826640 deriving (GHC.Generic,Show,Eq,Ord,NFData)
827−instance RenderSQL (FromClause outer commons schemas params from) where
828− renderSQL = renderFromClause
829641
830−-- | A real `table` is a table from the database.
642+-- | A real `table` is a table from the schema.
831643table
832− :: (Has sch schemas schema, Has tab schema ('Table table))
833− => Aliased (QualifiedAlias sch) (alias ::: tab)
834− -> FromClause outer commons schemas params '[alias ::: TableToRow table]
644+ :: Has tab schema ('Table table)
645+ => Aliased Alias (alias ::: tab)
646+ -> FromClause schema params '[alias ::: TableToRelation table]
835647table (tab `As` alias) = UnsafeFromClause $
836− renderSQL tab <+> "AS" <+> renderSQL alias
648+ renderAlias tab <+> "AS" <+> renderAlias alias
837649
838650-- | `subquery` derives a table from a `Query`.
839651subquery
840− :: Aliased (Query outer commons schemas params) query
841− -> FromClause outer commons schemas params '[query]
842−subquery = UnsafeFromClause . renderAliased (parenthesized . renderSQL)
652+ :: Aliased (Query schema params) rel
653+ -> FromClause schema params '[rel]
654+subquery = UnsafeFromClause . renderAliasedAs (parenthesized . renderQuery)
843655
844656-- | `view` derives a table from a `View`.
845657view
846− :: (Has sch schemas schema, Has vw schema ('View view))
847− => Aliased (QualifiedAlias sch) (alias ::: vw)
848− -> FromClause outer commons schemas params '[alias ::: view]
658+ :: Has view schema ('View rel)
659+ => Aliased Alias (alias ::: view)
660+ -> FromClause schema params '[alias ::: rel]
849661view (vw `As` alias) = UnsafeFromClause $
850− renderSQL vw <+> "AS" <+> renderSQL alias
851−
852−-- | `common` derives a table from a common table expression.
853−common
854− :: Has cte commons common
855− => Aliased Alias (alias ::: cte)
856− -> FromClause outer commons schemas params '[alias ::: common]
857−common (cte `As` alias) = UnsafeFromClause $
858− renderSQL cte <+> "AS" <+> renderSQL alias
859−
860−instance Additional (FromClause outer commons schemas params) where
861− also right left = UnsafeFromClause $
862− renderSQL left <> ", " <> renderSQL right
662+ renderAlias vw <+> "AS" <+> renderAlias alias
863663
864−{- |
865−@left & crossJoin right@. For every possible combination of rows from
866−@left@ and @right@ (i.e., a Cartesian product), the joined table will contain
867−a row consisting of all columns in @left@ followed by all columns in @right@.
868−If the tables have @n@ and @m@ rows respectively, the joined table will
869−have @n * m@ rows.
664+{- | @left & crossJoin right@. For every possible combination of rows from
665+ @left@ and @right@ (i.e., a Cartesian product), the joined table will contain
666+ a row consisting of all columns in @left@ followed by all columns in @right@.
667+ If the tables have @n@ and @m@ rows respectively, the joined table will
668+ have @n * m@ rows.
870669-}
871670crossJoin
872− :: FromClause outer commons schemas params right
671+ :: FromClause schema params right
873672 -- ^ right
874− -> FromClause outer commons schemas params left
673+ -> FromClause schema params left
875674 -- ^ left
876− -> FromClause outer commons schemas params (Join left right)
675+ -> FromClause schema params (Join left right)
877676crossJoin right left = UnsafeFromClause $
878− renderSQL left <+> "CROSS JOIN" <+> renderSQL right
677+ renderFromClause left <+> "CROSS JOIN" <+> renderFromClause right
879678
880679{- | @left & innerJoin right on@. The joined table is filtered by
881680the @on@ condition.
882681-}
883682innerJoin
884− :: FromClause outer commons schemas params right
683+ :: FromClause schema params right
885684 -- ^ right
886− -> Condition outer commons 'Ungrouped schemas params (Join left right)
685+ -> Condition schema (Join left right) 'Ungrouped params
887686 -- ^ @on@ condition
888− -> FromClause outer commons schemas params left
687+ -> FromClause schema params left
889688 -- ^ left
890− -> FromClause outer commons schemas params (Join left right)
689+ -> FromClause schema params (Join left right)
891690innerJoin right on left = UnsafeFromClause $
892− renderSQL left <+> "INNER JOIN" <+> renderSQL right
893− <+> "ON" <+> renderSQL on
691+ renderFromClause left <+> "INNER JOIN" <+> renderFromClause right
692+ <+> "ON" <+> renderExpression on
894693
895694{- | @left & leftOuterJoin right on@. First, an inner join is performed.
896695 Then, for each row in @left@ that does not satisfy the @on@ condition with
@@ -898,16 +697,16 @@ innerJoin right on left = UnsafeFromClause $
898697 Thus, the joined table always has at least one row for each row in @left@.
899698-}
900699leftOuterJoin
901− :: FromClause outer commons schemas params right
700+ :: FromClause schema params right
902701 -- ^ right
903− -> Condition outer commons 'Ungrouped schemas params (Join left right)
702+ -> Condition schema (Join left right) 'Ungrouped params
904703 -- ^ @on@ condition
905− -> FromClause outer commons schemas params left
704+ -> FromClause schema params left
906705 -- ^ left
907− -> FromClause outer commons schemas params (Join left (NullifyFrom right))
706+ -> FromClause schema params (Join left (NullifyRelations right))
908707leftOuterJoin right on left = UnsafeFromClause $
909− renderSQL left <+> "LEFT OUTER JOIN" <+> renderSQL right
910− <+> "ON" <+> renderSQL on
708+ renderFromClause left <+> "LEFT OUTER JOIN" <+> renderFromClause right
709+ <+> "ON" <+> renderExpression on
911710
912711{- | @left & rightOuterJoin right on@. First, an inner join is performed.
913712 Then, for each row in @right@ that does not satisfy the @on@ condition with
@@ -916,16 +715,16 @@ leftOuterJoin right on left = UnsafeFromClause $
916715 have a row for each row in @right@.
917716-}
918717rightOuterJoin
919− :: FromClause outer commons schemas params right
718+ :: FromClause schema params right
920719 -- ^ right
921− -> Condition outer commons 'Ungrouped schemas params (Join left right)
720+ -> Condition schema (Join left right) 'Ungrouped params
922721 -- ^ @on@ condition
923− -> FromClause outer commons schemas params left
722+ -> FromClause schema params left
924723 -- ^ left
925− -> FromClause outer commons schemas params (Join (NullifyFrom left) right)
724+ -> FromClause schema params (Join (NullifyRelations left) right)
926725rightOuterJoin right on left = UnsafeFromClause $
927− renderSQL left <+> "RIGHT OUTER JOIN" <+> renderSQL right
928− <+> "ON" <+> renderSQL on
726+ renderFromClause left <+> "RIGHT OUTER JOIN" <+> renderFromClause right
727+ <+> "ON" <+> renderExpression on
929728
930729{- | @left & fullOuterJoin right on@. First, an inner join is performed.
931730 Then, for each row in @left@ that does not satisfy the @on@ condition with
@@ -935,46 +734,42 @@ rightOuterJoin right on left = UnsafeFromClause $
935734 is added.
936735-}
937736fullOuterJoin
938− :: FromClause outer commons schemas params right
737+ :: FromClause schema params right
939738 -- ^ right
940− -> Condition outer commons 'Ungrouped schemas params (Join left right)
739+ -> Condition schema (Join left right) 'Ungrouped params
941740 -- ^ @on@ condition
942− -> FromClause outer commons schemas params left
741+ -> FromClause schema params left
943742 -- ^ left
944− -> FromClause outer commons schemas params
945− (Join (NullifyFrom left) (NullifyFrom right))
743+ -> FromClause schema params
744+ (Join (NullifyRelations left) (NullifyRelations right))
946745fullOuterJoin right on left = UnsafeFromClause $
947− renderSQL left <+> "FULL OUTER JOIN" <+> renderSQL right
948− <+> "ON" <+> renderSQL on
746+ renderFromClause left <+> "FULL OUTER JOIN" <+> renderFromClause right
747+ <+> "ON" <+> renderExpression on
949748
950749{-----------------------------------------
951750Grouping
952751-----------------------------------------}
953752
954−-- | `By`s are used in `groupBy` to reference a list of columns which are then
753+-- | `By`s are used in `group` to reference a list of columns which are then
955754-- used to group together those rows in a table that have the same values
956755-- in all the columns listed. @By \#col@ will reference an unambiguous
957756-- column @col@; otherwise @By2 (\#tab \! \#col)@ will reference a table
958757-- qualified column @tab.col@.
959758data By
960− (from :: FromType)
759+ (relations :: RelationsType)
961760 (by :: (Symbol,Symbol)) where
962761 By1
963− :: (HasUnique table from columns, Has column columns ty)
762+ :: (HasUnique relation relations columns, Has column columns ty)
964763 => Alias column
965− -> By from '(table, column)
764+ -> By relations '(relation, column)
966765 By2
967− :: (Has table from columns, Has column columns ty)
968− => Alias table
766+ :: (Has relation relations columns, Has column columns ty)
767+ => Alias relation
969768 -> Alias column
970− -> By from '(table, column)
971−deriving instance Show (By from by)
972−deriving instance Eq (By from by)
973−deriving instance Ord (By from by)
974−instance RenderSQL (By from by) where
975− renderSQL = \case
976− By1 column -> renderSQL column
977− By2 rel column -> renderSQL rel <> "." <> renderSQL column
769+ -> By relations '(relation, column)
770+deriving instance Show (By relations by)
771+deriving instance Eq (By relations by)
772+deriving instance Ord (By relations by)
978773
979774instance (HasUnique rel rels cols, Has col cols ty, by ~ '(rel, col))
980775 => IsLabel col (By rels by) where fromLabel = By1 fromLabel
@@ -986,113 +781,94 @@ instance (Has rel rels cols, Has col cols ty, bys ~ '[ '(rel, col)])
986781 => IsQualified rel col (NP (By rels) bys) where
987782 rel ! col = By2 rel col :* Nil
988783
784+-- | Renders a `By`.
785+renderBy :: By relations by -> ByteString
786+renderBy = \case
787+ By1 column -> renderAlias column
788+ By2 rel column -> renderAlias rel <> "." <> renderAlias column
789+
989790-- | A `GroupByClause` indicates the `Grouping` of a `TableExpression`.
990791-- A `NoGroups` indicates `Ungrouped` while a `Group` indicates `Grouped`.
991792-- @NoGroups@ is distinguised from @Group Nil@ since no aggregation can be
992793-- done on @NoGroups@ while all output `Expression`s must be aggregated
993794-- in @Group Nil@. In general, all output `Expression`s in the
994795-- complement of @bys@ must be aggregated in @Group bys@.
995−newtype GroupByClause grp from = UnsafeGroupByClause
996− { renderGroupByClause :: ByteString }
997− deriving (GHC.Generic,Show,Eq,Ord,NFData)
998−instance RenderSQL (GroupByClause grp from) where
999− renderSQL = renderGroupByClause
1000−noGroups :: GroupByClause 'Ungrouped from
1001−noGroups = UnsafeGroupByClause ""
1002−group
1003− :: SListI bys
1004− => NP (By from) bys
1005− -> GroupByClause ('Grouped bys) from
1006−group bys = UnsafeGroupByClause $ case bys of
1007− Nil -> ""
1008− bys' -> " GROUP BY" <+> renderCommaSeparated renderSQL bys'
796+data GroupByClause relations grouping where
797+ NoGroups :: GroupByClause relations 'Ungrouped
798+ Group
799+ :: SListI bys
800+ => NP (By relations) bys
801+ -> GroupByClause relations ('Grouped bys)
802+
803+-- | Renders a `GroupByClause`.
804+renderGroupByClause :: GroupByClause relations grouping -> ByteString
805+renderGroupByClause = \case
806+ NoGroups -> ""
807+ Group Nil -> ""
808+ Group bys -> " GROUP BY" <+> renderCommaSeparated renderBy bys
1009809
1010810-- | A `HavingClause` is used to eliminate groups that are not of interest.
1011811-- An `Ungrouped` `TableExpression` may only use `NoHaving` while a `Grouped`
1012812-- `TableExpression` must use `Having` whose conditions are combined with
1013813-- `.&&`.
1014−data HavingClause outer commons grp schemas params from where
1015− NoHaving :: HavingClause outer commons 'Ungrouped schemas params from
814+data HavingClause schema relations grouping params where
815+ NoHaving :: HavingClause schema relations 'Ungrouped params
1016816 Having
1017− :: [Condition outer commons ('Grouped bys) schemas params from]
1018− -> HavingClause outer commons ('Grouped bys) schemas params from
1019−deriving instance Show (HavingClause outer commons grp schemas params from)
1020−deriving instance Eq (HavingClause outer commons grp schemas params from)
1021−deriving instance Ord (HavingClause outer commons grp schemas params from)
817+ :: [Condition schema relations ('Grouped bys) params]
818+ -> HavingClause schema relations ('Grouped bys) params
819+deriving instance Show (HavingClause schema relations grouping params)
820+deriving instance Eq (HavingClause schema relations grouping params)
821+deriving instance Ord (HavingClause schema relations grouping params)
1022822
1023823-- | Render a `HavingClause`.
1024−instance RenderSQL (HavingClause outer commons grp schemas params from) where
1025− renderSQL = \case
1026− NoHaving -> ""
1027− Having [] -> ""
1028− Having conditions ->
1029− " HAVING" <+> commaSeparated (renderSQL <$> conditions)
1030−
1031−-- | A `CommonTableExpression` is an auxiliary statement in a `with` clause.
1032−data CommonTableExpression statement
1033− (schemas :: SchemasType)
1034− (params :: [NullityType])
1035− (commons0 :: FromType)
1036− (commons1 :: FromType) where
1037− CommonTableExpression
1038− :: Aliased (statement commons schemas params) (cte ::: common)
1039− -> CommonTableExpression statement schemas params commons (cte ::: common ': commons)
1040−instance
1041− ( KnownSymbol cte
1042− , commons1 ~ (cte ::: common ': commons)
1043− ) => Aliasable cte
1044− (statement commons schemas params common)
1045− (CommonTableExpression statement schemas params commons commons1) where
1046− statement `as` cte = CommonTableExpression (statement `as` cte)
1047−instance
1048− ( KnownSymbol cte
1049− , commons1 ~ (cte ::: common ': commons)
1050− ) => Aliasable cte
1051− (statement commons schemas params common)
1052− (Path (CommonTableExpression statement schemas params) commons commons1) where
1053− statement `as` cte = csingleton (statement `as` cte)
1054−
1055−instance (forall c s p r. RenderSQL (statement c s p r)) => RenderSQL
1056− (CommonTableExpression statement schemas params commons0 commons1) where
1057− renderSQL (CommonTableExpression (statement `As` cte)) =
1058− renderSQL cte <+> "AS" <+> parenthesized (renderSQL statement)
1059−
1060−-- | `with` provides a way to write auxiliary statements for use in a larger query.
1061−-- These statements, referred to as `CommonTableExpression`s, can be thought of as
1062−-- defining temporary tables that exist just for one query.
1063−class With statement where
1064− with
1065− :: Path (CommonTableExpression statement schemas params) commons0 commons1
1066− -- ^ common table expressions
1067− -> statement commons1 schemas params row
1068− -- ^ larger query
1069− -> statement commons0 schemas params row
1070−instance With (Query outer) where
1071− with Done query = query
1072− with ctes query = UnsafeQuery $
1073− "WITH" <+> commaSeparated (ctoList renderSQL ctes) <+> renderSQL query
824+renderHavingClause :: HavingClause schema relations grouping params -> ByteString
825+renderHavingClause = \case
826+ NoHaving -> ""
827+ Having [] -> ""
828+ Having conditions ->
829+ " HAVING" <+> commaSeparated (renderExpression <$> conditions)
1074830
1075−{- |
1076−>>> import Data.Monoid (Sum (..))
1077−>>> import Data.Int (Int64)
1078−>>> :{
1079− let
1080− query :: Query_ schema () (Sum Int64)
1081− query = withRecursive
1082− ( values_ ((1 & astype int) `as` #n)
1083− `unionAll`
1084− select_ ((#n + 1) `as` #n)
1085− (from (common #t) & where_ (#n .< 100)) `as` #t )
1086− ( select_ (fromNull 0 (sum_ (All #n)) `as` #getSum) (from (common #t) & groupBy Nil))
1087− in printSQL query
1088−:}
1089−WITH RECURSIVE "t" AS ((SELECT * FROM (VALUES ((1 :: int))) AS t ("n")) UNION ALL (SELECT ("n" + 1) AS "n" FROM "t" AS "t" WHERE ("n" < 100))) SELECT COALESCE(sum(ALL "n"), 0) AS "getSum" FROM "t" AS "t"
1090−-}
1091−withRecursive
1092− :: Aliased (Query outer (recursive ': commons) schemas params) recursive
1093− -> Query outer (recursive ': commons) schemas params row
1094− -> Query outer commons schemas params row
1095−withRecursive (recursive `As` cte) query = UnsafeQuery $
1096− "WITH RECURSIVE" <+> renderSQL cte
1097− <+> "AS" <+> parenthesized (renderSQL recursive)
1098− <+> renderSQL query
831+{-----------------------------------------
832+Sorting
833+-----------------------------------------}
834+
835+-- | `SortExpression`s are used by `sortBy` to optionally sort the results
836+-- of a `Query`. `Asc` or `Desc` set the sort direction of a `NotNull` result
837+-- column to ascending or descending. Ascending order puts smaller values
838+-- first, where "smaller" is defined in terms of the `.<` operator. Similarly,
839+-- descending order is determined with the `.>` operator. `AscNullsFirst`,
840+-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to
841+-- determine whether nulls appear before or after non-null values in the sort
842+-- ordering of a `Null` result column.
843+data SortExpression schema relations grouping params where
844+ Asc
845+ :: Expression schema relations grouping params ('NotNull ty)
846+ -> SortExpression schema relations grouping params
847+ Desc
848+ :: Expression schema relations grouping params ('NotNull ty)
849+ -> SortExpression schema relations grouping params
850+ AscNullsFirst
851+ :: Expression schema relations grouping params ('Null ty)
852+ -> SortExpression schema relations grouping params
853+ AscNullsLast
854+ :: Expression schema relations grouping params ('Null ty)
855+ -> SortExpression schema relations grouping params
856+ DescNullsFirst
857+ :: Expression schema relations grouping params ('Null ty)
858+ -> SortExpression schema relations grouping params
859+ DescNullsLast
860+ :: Expression schema relations grouping params ('Null ty)
861+ -> SortExpression schema relations grouping params
862+deriving instance Show (SortExpression schema relations grouping params)
863+
864+-- | Render a `SortExpression`.
865+renderSortExpression :: SortExpression schema relations grouping params -> ByteString
866+renderSortExpression = \case
867+ Asc expression -> renderExpression expression <+> "ASC"
868+ Desc expression -> renderExpression expression <+> "DESC"
869+ AscNullsFirst expression -> renderExpression expression
870+ <+> "ASC NULLS FIRST"
871+ DescNullsFirst expression -> renderExpression expression
872+ <+> "DESC NULLS FIRST"
873+ AscNullsLast expression -> renderExpression expression <+> "ASC NULLS LAST"
874+ DescNullsLast expression -> renderExpression expression <+> "DESC NULLS LAST"