@@ -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 +9,68 @@ Squeal queries.
99-}
1010
1111{-# LANGUAGE
12− ConstraintKinds
12+ DataKinds
13+ , DeriveDataTypeable
1314 , DeriveGeneric
14− , FlexibleContexts
1515 , FlexibleInstances
1616 , GADTs
1717 , GeneralizedNewtypeDeriving
18+ , KindSignatures
1819 , LambdaCase
1920 , MultiParamTypeClasses
20− , OverloadedLabels
2121 , OverloadedStrings
22− , QuantifiedConstraints
2322 , ScopedTypeVariables
2423 , StandaloneDeriving
2524 , TypeApplications
26− , TypeFamilies
2725 , TypeInType
2826 , TypeOperators
29− , RankNTypes
3027 , UndecidableInstances
31− #-}
28+#-}
3229
3330module Squeal.PostgreSQL.Query
3431 ( -- * 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
32+ Query (UnsafeQuery, renderQuery)
4933 , union
5034 , unionAll
5135 , intersect
5236 , intersectAll
5337 , except
5438 , exceptAll
55− -- ** With
56− , With (..)
57− , CommonTableExpression (..)
58− , withRecursive
39+ -- * Select
40+ , select
41+ , selectDistinct
42+ , selectStar
43+ , selectDistinctStar
44+ , selectDotStar
45+ , selectDistinctDotStar
5946 -- * Table Expressions
6047 , TableExpression (..)
48+ , renderTableExpression
6149 , from
6250 , where_
63− , groupBy
51+ , group
6452 , having
53+ , orderBy
6554 , limit
6655 , offset
67− -- * From Clauses
56+ -- * From
6857 , FromClause (..)
69− , table
70− , subquery
71− , view
72− , common
73− , crossJoin
74− , innerJoin
75− , leftOuterJoin
76− , rightOuterJoin
77− , fullOuterJoin
58+ , renderFromClause
7859 -- * Grouping
79− , By (..)
80− , GroupByClause (..)
81− , HavingClause (..)
60+ , By (By, By2)
61+ , renderBy
62+ , GroupByClause (NoGroups, Group)
63+ , renderGroupByClause
64+ , HavingClause (NoHaving, Having)
65+ , renderHavingClause
66+ -- * Sorting
67+ , SortExpression (..)
68+ , renderSortExpression
8269 ) where
8370
8471import Control.DeepSeq
8572import Data.ByteString (ByteString)
86−import Data.Kind (Type)
73+import Data.Monoid
8774import Data.String
8875import Data.Word
8976import Generics.SOP hiding (from)
@@ -91,577 +78,165 @@ import GHC.TypeLits
9178
9279import qualified GHC.Generics as GHC
9380
94−import Squeal.PostgreSQL.Alias
9581import 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
101−import Squeal.PostgreSQL.Render
82+import Squeal.PostgreSQL.Prettyprint
10283import Squeal.PostgreSQL.Schema
10384
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−
111−{- |
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−-}
85+-- | The process of retrieving or the command to retrieve data from a database
86+-- is called a `Query`. The `select`, `selectStar`, `selectDotStar`,
87+-- `selectDistinct`, `selectDistinctStar` and `selectDistinctDotStar` commands
88+-- are used to specify queries.
12389newtype Query
124− (outer :: FromType)
125− (commons :: FromType)
126− (schemas :: SchemasType)
127− (params :: [NullityType])
128− (row :: RowType)
90+ (schema :: TablesType)
91+ (params :: [ColumnType])
92+ (columns :: ColumnsType)
12993 = UnsafeQuery { renderQuery :: ByteString }
13094 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−:}
155−
156−simple query:
157−
158−>>> type Columns = '["col1" ::: 'NoDef :=> 'NotNull 'PGint4, "col2" ::: 'NoDef :=> 'NotNull 'PGint4]
159−>>> type Schema = '["tab" ::: 'Table ('[] :=> Columns)]
160−>>> :{
161−let
162− query :: Query_ (Public Schema) () (Row Int32 Int32)
163− query = select Star (from (table #tab))
164−in printSQL query
165−:}
166−SELECT * FROM "tab" AS "tab"
167−
168−restricted query:
169−
170−>>> :{
171−let
172− query :: Query_ (Public Schema) () (Row Int32 Int32)
173− query =
174− select_ ((#col1 + #col2) `as` #col1 :* #col1 `as` #col2)
175− ( from (table #tab)
176− & where_ (#col1 .> #col2)
177− & where_ (#col2 .> 0) )
178−in printSQL query
179−:}
180−SELECT ("col1" + "col2") AS "col1", "col1" AS "col2" FROM "tab" AS "tab" WHERE (("col1" > "col2") AND ("col2" > 0))
181−
182−subquery:
183−
184−>>> :{
185−let
186− query :: Query_ (Public Schema) () (Row Int32 Int32)
187− query = select Star (from (subquery (select Star (from (table #tab)) `as` #sub)))
188−in printSQL query
189−:}
190−SELECT * FROM (SELECT * FROM "tab" AS "tab") AS "sub"
191−
192−limits and offsets:
193−
194−>>> :{
195−let
196− query :: Query_ (Public Schema) () (Row Int32 Int32)
197− query = select Star (from (table #tab) & limit 100 & offset 2 & limit 50 & offset 2)
198−in printSQL query
199−:}
200−SELECT * FROM "tab" AS "tab" LIMIT 50 OFFSET 4
201−
202−parameterized query:
203−
204−>>> :{
205−let
206− query :: Query_ (Public Schema) (Only Int32) (Row Int32 Int32)
207− query = select Star (from (table #tab) & where_ (#col1 .> param @1))
208−in printSQL query
209−:}
210−SELECT * FROM "tab" AS "tab" WHERE ("col1" > ($1 :: int4))
211−
212−aggregation query:
213−
214−>>> :{
215−let
216− query :: Query_ (Public Schema) () (Row Int64 Int32)
217− query =
218− select_ ((fromNull 0 (sum_ (All #col2))) `as` #col1 :* #col1 `as` #col2)
219− ( from (table (#tab `as` #table1))
220− & groupBy #col1
221− & having (sum_ (Distinct #col2) .> 1) )
222−in printSQL query
223−:}
224−SELECT COALESCE(sum(ALL "col2"), 0) AS "col1", "col1" AS "col2" FROM "tab" AS "table1" GROUP BY "col1" HAVING (sum(DISTINCT "col2") > 1)
225−
226−sorted query:
227−
228−>>> :{
229−let
230− query :: Query_ (Public Schema) () (Row Int32 Int32)
231− query = select Star (from (table #tab) & orderBy [#col1 & Asc])
232−in printSQL query
233−:}
234−SELECT * FROM "tab" AS "tab" ORDER BY "col1" ASC
235−
236−joins:
237−
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−
273−>>> :{
274−let
275− query :: Query_ (Public OrdersSchema) () Order
276− query = select_
277− ( #o ! #price `as` #price :*
278− #c ! #name `as` #customerName :*
279− #s ! #name `as` #shipperName )
280− ( from (table (#orders `as` #o)
281− & innerJoin (table (#customers `as` #c))
282− (#o ! #customer_id .== #c ! #id)
283− & innerJoin (table (#shippers `as` #s))
284− (#o ! #shipper_id .== #s ! #id)) )
285−in printSQL query
286−:}
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")
288−
289−self-join:
290−
291−>>> :{
292−let
293− query :: Query_ (Public Schema) () (Row Int32 Int32)
294− query = select
295− (#t1 & DotStar)
296− (from (table (#tab `as` #t1) & crossJoin (table (#tab `as` #t2))))
297−in printSQL query
298−:}
299−SELECT "t1".* FROM "tab" AS "t1" CROSS JOIN "tab" AS "t2"
300−
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−
313−set operations:
314−
315−>>> :{
316−let
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)
353− 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)))))
358−in printSQL query
359−:}
360−SELECT "col1" AS "fromOnly" FROM "tab" AS "t1" WHERE EXISTS (SELECT * FROM "tab" AS "t2" WHERE ("t2"."col2" = "t1"."col1"))
361−
362−-}
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)
36995
37096-- | The results of two queries can be combined using the set operation
371−-- `union`. Duplicate rows are eliminated.
97+-- `union`. Duplicate rows are eliminated.
37298union
373− :: Query outer commons schemas params columns
374− -> Query outer commons schemas params columns
375− -> Query outer commons schemas params columns
99+ :: Query schema params columns
100+ -> Query schema params columns
101+ -> Query schema params columns
376102q1 `union` q2 = UnsafeQuery $
377− parenthesized (renderSQL q1)
103+ parenthesized (renderQuery q1)
378104 <+> "UNION"
379− <+> parenthesized (renderSQL q2)
105+ <+> parenthesized (renderQuery q2)
380106
381107-- | The results of two queries can be combined using the set operation
382108-- `unionAll`, the disjoint union. Duplicate rows are retained.
383109unionAll
384− :: Query outer commons schemas params columns
385− -> Query outer commons schemas params columns
386− -> Query outer commons schemas params columns
110+ :: Query schema params columns
111+ -> Query schema params columns
112+ -> Query schema params columns
387113q1 `unionAll` q2 = UnsafeQuery $
388− parenthesized (renderSQL q1)
114+ parenthesized (renderQuery q1)
389115 <+> "UNION" <+> "ALL"
390− <+> parenthesized (renderSQL q2)
116+ <+> parenthesized (renderQuery q2)
391117
392118-- | The results of two queries can be combined using the set operation
393119-- `intersect`, the intersection. Duplicate rows are eliminated.
394120intersect
395− :: Query outer commons schemas params columns
396− -> Query outer commons schemas params columns
397− -> Query outer commons schemas params columns
121+ :: Query schema params columns
122+ -> Query schema params columns
123+ -> Query schema params columns
398124q1 `intersect` q2 = UnsafeQuery $
399− parenthesized (renderSQL q1)
125+ parenthesized (renderQuery q1)
400126 <+> "INTERSECT"
401− <+> parenthesized (renderSQL q2)
127+ <+> parenthesized (renderQuery q2)
402128
403129-- | The results of two queries can be combined using the set operation
404130-- `intersectAll`, the intersection. Duplicate rows are retained.
405131intersectAll
406− :: Query outer commons schemas params columns
407− -> Query outer commons schemas params columns
408− -> Query outer commons schemas params columns
132+ :: Query schema params columns
133+ -> Query schema params columns
134+ -> Query schema params columns
409135q1 `intersectAll` q2 = UnsafeQuery $
410− parenthesized (renderSQL q1)
136+ parenthesized (renderQuery q1)
411137 <+> "INTERSECT" <+> "ALL"
412− <+> parenthesized (renderSQL q2)
138+ <+> parenthesized (renderQuery q2)
413139
414140-- | The results of two queries can be combined using the set operation
415141-- `except`, the set difference. Duplicate rows are eliminated.
416142except
417− :: Query outer commons schemas params columns
418− -> Query outer commons schemas params columns
419− -> Query outer commons schemas params columns
143+ :: Query schema params columns
144+ -> Query schema params columns
145+ -> Query schema params columns
420146q1 `except` q2 = UnsafeQuery $
421− parenthesized (renderSQL q1)
147+ parenthesized (renderQuery q1)
422148 <+> "EXCEPT"
423− <+> parenthesized (renderSQL q2)
149+ <+> parenthesized (renderQuery q2)
424150
425151-- | The results of two queries can be combined using the set operation
426152-- `exceptAll`, the set difference. Duplicate rows are retained.
427153exceptAll
428− :: Query outer commons schemas params columns
429− -> Query outer commons schemas params columns
430− -> Query outer commons schemas params columns
154+ :: Query schema params columns
155+ -> Query schema params columns
156+ -> Query schema params columns
431157q1 `exceptAll` q2 = UnsafeQuery $
432− parenthesized (renderSQL q1)
158+ parenthesized (renderQuery q1)
433159 <+> "EXCEPT" <+> "ALL"
434− <+> parenthesized (renderSQL q2)
160+ <+> parenthesized (renderQuery q2)
435161
436162{-----------------------------------------
437163SELECT queries
438164-----------------------------------------}
439165
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−
525166-- | the `TableExpression` in the `select` command constructs an intermediate
526167-- virtual table by possibly combining tables, views, eliminating rows,
527168-- grouping, etc. This table is finally passed on to processing by
528−-- the select list. The `Selection` determines which columns of
169+-- the select list. The select list determines which columns of
529170-- the intermediate table are actually output.
530171select
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
172+ :: SListI columns
173+ => NP (Aliased (Expression tables grouping params)) (column ': columns)
547174 -- ^ select list
548− -> TableExpression outer commons grp schemas params from
175+ -> TableExpression schema params tables grouping
549176 -- ^ intermediate virtual table
550− -> Query outer commons schemas params row
551−select_ = select . List
177+ -> Query schema params (column ': columns)
178+select list tabs = UnsafeQuery $
179+ "SELECT"
180+ <+> renderCommaSeparated (renderAliased renderExpression) list
181+ <+> renderTableExpression tabs
552182
553183-- | After the select list has been processed, the result table can
554184-- be subject to the elimination of duplicate rows using `selectDistinct`.
555185selectDistinct
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
186+ :: SListI columns
187+ => NP (Aliased (Expression tables 'Ungrouped params)) (column ': columns)
188+ -- ^ select list
189+ -> TableExpression schema params tables 'Ungrouped
560190 -- ^ intermediate virtual table
561− -> Query outer commons schemas params columns
562−selectDistinct selection tabexpr = UnsafeQuery $
191+ -> Query schema params (column ': columns)
192+selectDistinct list tabs = UnsafeQuery $
563193 "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
194+ <+> renderCommaSeparated (renderAliased renderExpression) list
195+ <+> renderTableExpression tabs
196+
197+-- | The simplest kind of query is `selectStar` which emits all columns
198+-- that the table expression produces.
199+selectStar
200+ :: HasUnique table tables columns
201+ => TableExpression schema params tables 'Ungrouped
574202 -- ^ 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
203+ -> Query schema params columns
204+selectStar tabs = UnsafeQuery $ "SELECT" <+> "*" <+> renderTableExpression tabs
205+
206+-- | A `selectDistinctStar` emits all columns that the table expression
207+-- produces and eliminates duplicate rows.
208+selectDistinctStar
209+ :: HasUnique table tables columns
210+ => TableExpression schema params tables 'Ungrouped
598211 -- ^ 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
212+ -> Query schema params columns
213+selectDistinctStar tabs = UnsafeQuery $
214+ "SELECT DISTINCT" <+> "*" <+> renderTableExpression tabs
215+
216+-- | When working with multiple tables, it can also be useful to ask
217+-- for all the columns of a particular table, using `selectDotStar`.
218+selectDotStar
219+ :: HasTable table tables columns
220+ => Alias table
221+ -- ^ particular virtual subtable
222+ -> TableExpression schema params tables 'Ungrouped
623223 -- ^ intermediate virtual table
624− -> Query outer commons schemas params columns
625−selectDistinctOn_ distincts = selectDistinctOn distincts . List
626−
627−-- | `values` computes a row value or set of row values
628−-- specified by value expressions. It is most commonly used
629−-- to generate a “constant table” within a larger command,
630−-- but it can be used on its own.
631−--
632−-- >>> type Row = '["a" ::: 'NotNull 'PGint4, "b" ::: 'NotNull 'PGtext]
633−-- >>> let query = values (1 `as` #a :* "one" `as` #b) [] :: Query outer commons schemas '[] Row
634−-- >>> printSQL query
635−-- SELECT * FROM (VALUES (1, E'one')) AS t ("a", "b")
636−values
637− :: SListI cols
638− => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
639− -> [NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols]
640− -- ^ When more than one row is specified, all the rows must
641− -- must have the same number of elements
642− -> Query outer commons schemas params cols
643−values rw rws = UnsafeQuery $ "SELECT * FROM"
644− <+> parenthesized (
645− "VALUES"
646− <+> commaSeparated
647− ( parenthesized
648− . renderCommaSeparated renderValuePart <$> rw:rws )
649− ) <+> "AS t"
650− <+> parenthesized (renderCommaSeparated renderAliasPart rw)
651− where
652− renderAliasPart, renderValuePart
653− :: Aliased (Expression outer commons 'Ungrouped schemas params '[] ) ty -> ByteString
654− renderAliasPart (_ `As` name) = renderSQL name
655− renderValuePart (value `As` _) = renderSQL value
656−
657−-- | `values_` computes a row value or set of row values
658−-- specified by value expressions.
659−values_
660− :: SListI cols
661− => NP (Aliased (Expression outer commons 'Ungrouped schemas params '[] )) cols
662− -- ^ one row of values
663− -> Query outer commons schemas params cols
664−values_ rw = values rw []
224+ -> Query schema params columns
225+selectDotStar table tables = UnsafeQuery $
226+ "SELECT" <+> renderAlias table <> ".*" <+> renderTableExpression tables
227+
228+-- | A `selectDistinctDotStar` asks for all the columns of a particular table,
229+-- and eliminates duplicate rows.
230+selectDistinctDotStar
231+ :: HasTable table tables columns
232+ => Alias table
233+ -- ^ particular virtual subtable
234+ -> TableExpression schema params tables 'Ungrouped
235+ -- ^ intermediate virtual table
236+ -> Query schema params columns
237+selectDistinctDotStar table tables = UnsafeQuery $
238+ "SELECT DISTINCT" <+> renderAlias table <> ".*"
239+ <+> renderTableExpression tables
665240
666241{-----------------------------------------
667242Table Expressions
@@ -674,17 +249,15 @@ Table Expressions
674249-- to a table on disk, a so-called base table, but more complex expressions
675250-- can be used to modify or combine base tables in various ways.
676251data TableExpression
677− (outer :: FromType)
678− (commons :: FromType)
679− (grp :: Grouping)
680− (schemas :: SchemasType)
681− (params :: [NullityType])
682− (from :: FromType)
252+ (schema :: TablesType)
253+ (params :: [ColumnType])
254+ (tables :: TablesType)
255+ (grouping :: Grouping)
683256 = TableExpression
684− { fromClause :: FromClause outer commons schemas params from
257+ { fromClause :: FromClause schema params tables
685258 -- ^ A table reference that can be a table name, or a derived table such
686259 -- as a subquery, a @JOIN@ construct, or complex combinations of these.
687− , whereClause :: [Condition outer commons 'Ungrouped schemas params from]
260+ , whereClause :: [Condition tables 'Ungrouped params]
688261 -- ^ optional search coditions, combined with `.&&`. After the processing
689262 -- of the `fromClause` is done, each row of the derived virtual table
690263 -- is checked against the search condition. If the result of the
@@ -693,20 +266,20 @@ data TableExpression
693266 -- at least one column of the table generated in the `fromClause`;
694267 -- this is not required, but otherwise the WHERE clause will
695268 -- be fairly useless.
696− , groupByClause :: GroupByClause grp from
269+ , groupByClause :: GroupByClause tables grouping
697270 -- ^ The `groupByClause` is used to group together those rows in a table
698271 -- that have the same values in all the columns listed. The order in which
699272 -- the columns are listed does not matter. The effect is to combine each
700273 -- set of rows having common values into one group row that represents all
701274 -- rows in the group. This is done to eliminate redundancy in the output
702275 -- and/or compute aggregates that apply to these groups.
703− , havingClause :: HavingClause outer commons grp schemas params from
276+ , havingClause :: HavingClause tables grouping params
704277 -- ^ If a table has been grouped using `groupBy`, but only certain groups
705278 -- are of interest, the `havingClause` can be used, much like a
706279 -- `whereClause`, to eliminate groups from the result. Expressions in the
707280 -- `havingClause` can refer both to grouped expressions and to ungrouped
708281 -- expressions (which necessarily involve an aggregate function).
709− , orderByClause :: [SortExpression outer commons grp schemas params from]
282+ , orderByClause :: [SortExpression tables grouping params]
710283 -- ^ The `orderByClause` is for optional sorting. When more than one
711284 -- `SortExpression` is specified, the later (right) values are used to sort
712285 -- rows that are equal according to the earlier (left) values.
@@ -716,102 +289,110 @@ data TableExpression
716289 -- will be returned (but possibly fewer, if the query itself yields
717290 -- fewer rows).
718291 , offsetClause :: [Word64]
719− -- ^ The `offsetClause` is combined with `Prelude.+` to give an offset count
292+ -- ^ The `offsetClause` is combined with `+` to give an offset count
720293 -- if nonempty. The offset count says to skip that many rows before
721294 -- beginning to return rows. The rows are skipped before the limit count
722295 -- is applied.
723− } deriving (GHC.Generic)
296+ }
724297
725298-- | 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 <$> srts)
745− renderLimits = \case
746− [] -> ""
747− lims -> " LIMIT" <+> fromString (show (minimum lims))
748− renderOffsets = \case
749− [] -> ""
750− offs -> " OFFSET" <+> fromString (show (sum offs))
299+renderTableExpression
300+ :: TableExpression schema params tables grouping
301+ -> ByteString
302+renderTableExpression
303+ (TableExpression tables whs' grps' hvs' srts' lims' offs') = mconcat
304+ [ "FROM ", renderFromClause tables
305+ , renderWheres whs'
306+ , renderGroupByClause grps'
307+ , renderHavingClause hvs'
308+ , renderSorts srts'
309+ , renderLimits lims'
310+ , renderOffsets offs'
311+ ]
312+ where
313+ renderWheres = \case
314+ [] -> ""
315+ wh:[] -> " WHERE" <+> renderExpression wh
316+ wh:whs -> " WHERE" <+> renderExpression (foldr (.&&) wh whs)
317+ renderSorts = \case
318+ [] -> ""
319+ srts -> " SORT BY"
320+ <+> commaSeparated (renderSortExpression <$> srts)
321+ renderLimits = \case
322+ [] -> ""
323+ lims -> " LIMIT" <+> fromString (show (minimum lims))
324+ renderOffsets = \case
325+ [] -> ""
326+ offs -> " OFFSET" <+> fromString (show (sum offs))
751327
752328-- | A `from` generates a `TableExpression` from a table reference that can be
753329-- a table name, or a derived table such as a subquery, a JOIN construct,
754330-- or complex combinations of these. A `from` may be transformed by `where_`,
755−-- `groupBy`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
331+-- `group`, `having`, `orderBy`, `limit` and `offset`, using the `&` operator
756332-- to match the left-to-right sequencing of their placement in SQL.
757333from
758− :: FromClause outer commons schemas params from -- ^ table reference
759− -> TableExpression outer commons 'Ungrouped schemas params from
760−from tab = TableExpression tab [] noGroups NoHaving [] [] []
334+ :: FromClause schema params tables -- ^ table reference
335+ -> TableExpression schema params tables 'Ungrouped
336+from tables = TableExpression tables [] NoGroups NoHaving [] [] []
761337
762338-- | A `where_` is an endomorphism of `TableExpression`s which adds a
763339-- search condition to the `whereClause`.
764340where_
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
768−where_ wh rels = rels {whereClause = wh : whereClause rels}
341+ :: Condition tables 'Ungrouped params
342+ -> TableExpression schema params tables grouping
343+ -> TableExpression schema params tables grouping
344+where_ wh tables = tables {whereClause = wh : whereClause tables}
769345
770−-- | A `groupBy` is a transformation of `TableExpression`s which switches
771−-- its `Grouping` from `Ungrouped` to `Grouped`. Use @groupBy Nil@ to perform
346+-- | A `group` is a transformation of `TableExpression`s which switches
347+-- its `Grouping` from `Ungrouped` to `Grouped`. Use @group Nil@ to perform
772348-- a "grand total" aggregation query.
773−groupBy
349+group
774350 :: 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
778−groupBy bys rels = TableExpression
779− { fromClause = fromClause rels
780− , whereClause = whereClause rels
781− , groupByClause = group bys
351+ => NP (By tables) bys
352+ -> TableExpression schema params tables 'Ungrouped
353+ -> TableExpression schema params tables ('Grouped bys)
354+group bys tables = TableExpression
355+ { fromClause = fromClause tables
356+ , whereClause = whereClause tables
357+ , groupByClause = Group bys
782358 , havingClause = Having []
783359 , orderByClause = []
784− , limitClause = limitClause rels
785− , offsetClause = offsetClause rels
360+ , limitClause = limitClause tables
361+ , offsetClause = offsetClause tables
786362 }
787363
788364-- | A `having` is an endomorphism of `TableExpression`s which adds a
789365-- search condition to the `havingClause`.
790366having
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
794−having hv rels = rels
795− { havingClause = case havingClause rels of Having hvs -> Having (hv:hvs) }
796−
797−instance OrderBy TableExpression where
798− orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}
367+ :: Condition tables ('Grouped bys) params
368+ -> TableExpression schema params tables ('Grouped bys)
369+ -> TableExpression schema params tables ('Grouped bys)
370+having hv tables = tables
371+ { havingClause = case havingClause tables of Having hvs -> Having (hv:hvs) }
372+
373+-- | An `orderBy` is an endomorphism of `TableExpression`s which appends an
374+-- ordering to the right of the `orderByClause`.
375+orderBy
376+ :: [SortExpression tables grouping params]
377+ -> TableExpression schema params tables grouping
378+ -> TableExpression schema params tables grouping
379+orderBy srts tables = tables {orderByClause = orderByClause tables ++ srts}
799380
800381-- | A `limit` is an endomorphism of `TableExpression`s which adds to the
801382-- `limitClause`.
802383limit
803− :: Word64 -- ^ limit parameter
804− -> TableExpression outer commons grp schemas params from
805− -> TableExpression outer commons grp schemas params from
806−limit lim rels = rels {limitClause = lim : limitClause rels}
384+ :: Word64
385+ -> TableExpression schema params tables grouping
386+ -> TableExpression schema params tables grouping
387+limit lim tables = tables {limitClause = lim : limitClause tables}
807388
808389-- | An `offset` is an endomorphism of `TableExpression`s which adds to the
809390-- `offsetClause`.
810391offset
811− :: Word64 -- ^ offset parameter
812− -> TableExpression outer commons grp schemas params from
813− -> TableExpression outer commons grp schemas params from
814−offset off rels = rels {offsetClause = off : offsetClause rels}
392+ :: Word64
393+ -> TableExpression schema params tables grouping
394+ -> TableExpression schema params tables grouping
395+offset off tables = tables {offsetClause = off : offsetClause tables}
815396
816397{-----------------------------------------
817398FROM clauses
@@ -820,279 +401,205 @@ FROM clauses
820401{- |
821402A `FromClause` can be a table name, or a derived table such
822403as a subquery, a @JOIN@ construct, or complex combinations of these.
823−-}
824−newtype FromClause outer commons schemas params from
825− = UnsafeFromClause { renderFromClause :: ByteString }
826− deriving (GHC.Generic,Show,Eq,Ord,NFData)
827−instance RenderSQL (FromClause outer commons schemas params from) where
828− renderSQL = renderFromClause
829404
830−-- | A real `table` is a table from the database.
831−table
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]
835−table (tab `As` alias) = UnsafeFromClause $
836− renderSQL tab <+> "AS" <+> renderSQL alias
405+* A real `Table` is a table from the schema.
837406
838−-- | `subquery` derives a table from a `Query`.
839−subquery
840− :: Aliased (Query outer commons schemas params) query
841− -> FromClause outer commons schemas params '[query]
842−subquery = UnsafeFromClause . renderAliased (parenthesized . renderSQL)
407+* `Subquery` derives a table from a `Query`.
843408
844−-- | `view` derives a table from a `View`.
845−view
846− :: (Has sch schemas schema, Has vw schema ('View view))
847− => Aliased (QualifiedAlias sch) (alias ::: vw)
848− -> FromClause outer commons schemas params '[alias ::: view]
849−view (vw `As` alias) = UnsafeFromClause $
850− renderSQL vw <+> "AS" <+> renderSQL alias
409+* A joined table is a table derived from two other (real or derived) tables
410+according to the rules of the particular join type. `CrossJoin`, `InnerJoin`,
411+`LeftOuterJoin`, `RightOuterJoin` and `FullOuterJoin` are available and can
412+be nested using the `&` operator to match the left-to-right sequencing of
413+their placement in SQL.
851414
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
415+ * @t1 & CrossJoin t2@. For every possible combination of rows from
416+ @t1@ and @t2@ (i.e., a Cartesian product), the joined table will contain
417+ a row consisting of all columns in @t1@ followed by all columns in @t2@.
418+ If the tables have @n@ and @m@ rows respectively, the joined table will
419+ have @n * m@ rows.
859420
860−instance Additional (FromClause outer commons schemas params) where
861− also right left = UnsafeFromClause $
862− renderSQL left <> ", " <> renderSQL right
421+ * @t1 & InnerJoin t2 on@. For each row @r1@ of @t1@, the joined
422+ table has a row for each row in @t2@ that satisfies the on @condition@
423+ with @r1@
863424
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.
870−-}
871−crossJoin
872− :: FromClause outer commons schemas params right
873− -- ^ right
874− -> FromClause outer commons schemas params left
875− -- ^ left
876− -> FromClause outer commons schemas params (Join left right)
877−crossJoin right left = UnsafeFromClause $
878− renderSQL left <+> "CROSS JOIN" <+> renderSQL right
879−
880−{- | @left & innerJoin right on@. The joined table is filtered by
881−the @on@ condition.
882−-}
883−innerJoin
884− :: FromClause outer commons schemas params right
885− -- ^ right
886− -> Condition outer commons 'Ungrouped schemas params (Join left right)
887− -- ^ @on@ condition
888− -> FromClause outer commons schemas params left
889− -- ^ left
890− -> FromClause outer commons schemas params (Join left right)
891−innerJoin right on left = UnsafeFromClause $
892− renderSQL left <+> "INNER JOIN" <+> renderSQL right
893− <+> "ON" <+> renderSQL on
894−
895−{- | @left & leftOuterJoin right on@. First, an inner join is performed.
896− Then, for each row in @left@ that does not satisfy the @on@ condition with
897− any row in @right@, a joined row is added with null values in columns of @right@.
898− Thus, the joined table always has at least one row for each row in @left@.
899−-}
900−leftOuterJoin
901− :: FromClause outer commons schemas params right
902− -- ^ right
903− -> Condition outer commons 'Ungrouped schemas params (Join left right)
904− -- ^ @on@ condition
905− -> FromClause outer commons schemas params left
906− -- ^ left
907− -> FromClause outer commons schemas params (Join left (NullifyFrom right))
908−leftOuterJoin right on left = UnsafeFromClause $
909− renderSQL left <+> "LEFT OUTER JOIN" <+> renderSQL right
910− <+> "ON" <+> renderSQL on
425+ * @t1 & LeftOuterJoin t2 on@. First, an inner join is performed.
426+ Then, for each row in @t1@ that does not satisfy the on @condition@ with
427+ any row in @t2@, a joined row is added with null values in columns of @t2@.
428+ Thus, the joined table always has at least one row for each row in @t1@.
911429
912−{- | @left & rightOuterJoin right on@. First, an inner join is performed.
913− Then, for each row in @right@ that does not satisfy the @on@ condition with
914− any row in @left@, a joined row is added with null values in columns of @left@.
430+ * @t1 & RightOuterJoin t2 on@. First, an inner join is performed.
431+ Then, for each row in @t2@ that does not satisfy the on condition with
432+ any row in @t1@, a joined row is added with null values in columns of @t1@.
915433 This is the converse of a left join: the result table will always
916− have a row for each row in @right@.
917−-}
918−rightOuterJoin
919− :: FromClause outer commons schemas params right
920− -- ^ right
921− -> Condition outer commons 'Ungrouped schemas params (Join left right)
922− -- ^ @on@ condition
923− -> FromClause outer commons schemas params left
924− -- ^ left
925− -> FromClause outer commons schemas params (Join (NullifyFrom left) right)
926−rightOuterJoin right on left = UnsafeFromClause $
927− renderSQL left <+> "RIGHT OUTER JOIN" <+> renderSQL right
928− <+> "ON" <+> renderSQL on
434+ have a row for each row in @t2@.
929435
930−{- | @left & fullOuterJoin right on@. First, an inner join is performed.
931− Then, for each row in @left@ that does not satisfy the @on@ condition with
932− any row in @right@, a joined row is added with null values in columns of @right@.
933− Also, for each row of @right@ that does not satisfy the join condition
934− with any row in @left@, a joined row with null values in the columns of @left@
436+ * @t1 & FullOuterJoin t2 on@. First, an inner join is performed.
437+ Then, for each row in @t1@ that does not satisfy the on condition with
438+ any row in @t2@, a joined row is added with null values in columns of @t2@.
439+ Also, for each row of @t2@ that does not satisfy the join condition
440+ with any row in @t1@, a joined row with null values in the columns of @t1@
935441 is added.
936442-}
937−fullOuterJoin
938− :: FromClause outer commons schemas params right
939− -- ^ right
940− -> Condition outer commons 'Ungrouped schemas params (Join left right)
941− -- ^ @on@ condition
942− -> FromClause outer commons schemas params left
943− -- ^ left
944− -> FromClause outer commons schemas params
945− (Join (NullifyFrom left) (NullifyFrom right))
946−fullOuterJoin right on left = UnsafeFromClause $
947− renderSQL left <+> "FULL OUTER JOIN" <+> renderSQL right
948− <+> "ON" <+> renderSQL on
443+data FromClause schema params tables where
444+ Table
445+ :: Aliased (Table schema) table
446+ -> FromClause schema params '[table]
447+ Subquery
448+ :: Aliased (Query schema params) table
449+ -> FromClause schema params '[table]
450+ CrossJoin
451+ :: FromClause schema params right
452+ -> FromClause schema params left
453+ -> FromClause schema params (Join left right)
454+ InnerJoin
455+ :: FromClause schema params right
456+ -> Condition (Join left right) 'Ungrouped params
457+ -> FromClause schema params left
458+ -> FromClause schema params (Join left right)
459+ LeftOuterJoin
460+ :: FromClause schema params right
461+ -> Condition (Join left right) 'Ungrouped params
462+ -> FromClause schema params left
463+ -> FromClause schema params (Join left (NullifyTables right))
464+ RightOuterJoin
465+ :: FromClause schema params right
466+ -> Condition (Join left right) 'Ungrouped params
467+ -> FromClause schema params left
468+ -> FromClause schema params (Join (NullifyTables left) right)
469+ FullOuterJoin
470+ :: FromClause schema params right
471+ -> Condition (Join left right) 'Ungrouped params
472+ -> FromClause schema params left
473+ -> FromClause schema params
474+ (Join (NullifyTables left) (NullifyTables right))
475+
476+-- | Renders a `FromClause`.
477+renderFromClause :: FromClause schema params tables -> ByteString
478+renderFromClause = \case
479+ Table table -> renderAliased renderTable table
480+ Subquery selection -> renderAliased (parenthesized . renderQuery) selection
481+ CrossJoin right left ->
482+ renderFromClause left <+> "CROSS JOIN" <+> renderFromClause right
483+ InnerJoin right on left -> renderJoin "INNER JOIN" right on left
484+ LeftOuterJoin right on left -> renderJoin "LEFT OUTER JOIN" right on left
485+ RightOuterJoin right on left -> renderJoin "RIGHT OUTER JOIN" right on left
486+ FullOuterJoin right on left -> renderJoin "FULL OUTER JOIN" right on left
487+ where
488+ renderJoin op right on left =
489+ renderFromClause left <+> op <+> renderFromClause right
490+ <+> "ON" <+> renderExpression on
949491
950492{-----------------------------------------
951493Grouping
952494-----------------------------------------}
953495
954−-- | `By`s are used in `groupBy` to reference a list of columns which are then
496+-- | `By`s are used in `group` to reference a list of columns which are then
955497-- used to group together those rows in a table that have the same values
956498-- in all the columns listed. @By \#col@ will reference an unambiguous
957−-- column @col@; otherwise @By2 (\#tab \! \#col)@ will reference a table
499+-- column @col@; otherwise @By2 \#tab \! \#col@ will reference a table
958500-- qualified column @tab.col@.
959501data By
960− (from :: FromType)
502+ (tables :: TablesType)
961503 (by :: (Symbol,Symbol)) where
962− By1
963− :: (HasUnique table from columns, Has column columns ty)
504+ By
505+ :: (HasUnique table tables columns, HasColumn column columns ty)
964506 => Alias column
965− -> By from '(table, column)
507+ -> By tables '(table, column)
966508 By2
967− :: (Has table from columns, Has column columns ty)
968− => Alias table
969− -> 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
978−
979−instance (HasUnique rel rels cols, Has col cols ty, by ~ '(rel, col))
980− => IsLabel col (By rels by) where fromLabel = By1 fromLabel
981−instance (HasUnique rel rels cols, Has col cols ty, bys ~ '[ '(rel, col)])
982− => IsLabel col (NP (By rels) bys) where fromLabel = By1 fromLabel :* Nil
983−instance (Has rel rels cols, Has col cols ty, by ~ '(rel, col))
984− => IsQualified rel col (By rels by) where (!) = By2
985−instance (Has rel rels cols, Has col cols ty, bys ~ '[ '(rel, col)])
986− => IsQualified rel col (NP (By rels) bys) where
987− rel ! col = By2 rel col :* Nil
509+ :: (HasTable table tables columns, HasColumn column columns ty)
510+ => (Alias table, Alias column)
511+ -> By tables '(table, column)
512+deriving instance Show (By tables by)
513+deriving instance Eq (By tables by)
514+deriving instance Ord (By tables by)
515+
516+-- | Renders a `By`.
517+renderBy :: By tables tabcolty -> ByteString
518+renderBy = \case
519+ By column -> renderAlias column
520+ By2 (table, column) -> renderAlias table <> "." <> renderAlias column
988521
989522-- | A `GroupByClause` indicates the `Grouping` of a `TableExpression`.
990523-- A `NoGroups` indicates `Ungrouped` while a `Group` indicates `Grouped`.
991524-- @NoGroups@ is distinguised from @Group Nil@ since no aggregation can be
992525-- done on @NoGroups@ while all output `Expression`s must be aggregated
993−-- in @Group Nil@. In general, all output `Expression`s in the
994−-- 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'
526+-- in @Group Nil@.
527+data GroupByClause tables grouping where
528+ NoGroups :: GroupByClause tables 'Ungrouped
529+ Group
530+ :: SListI bys
531+ => NP (By tables) bys
532+ -> GroupByClause tables ('Grouped bys)
533+
534+-- | Renders a `GroupByClause`.
535+renderGroupByClause :: GroupByClause tables grouping -> ByteString
536+renderGroupByClause = \case
537+ NoGroups -> ""
538+ Group Nil -> ""
539+ Group bys -> " GROUP BY" <+> renderCommaSeparated renderBy bys
1009540
1010541-- | A `HavingClause` is used to eliminate groups that are not of interest.
1011542-- An `Ungrouped` `TableExpression` may only use `NoHaving` while a `Grouped`
1012543-- `TableExpression` must use `Having` whose conditions are combined with
1013544-- `.&&`.
1014−data HavingClause outer commons grp schemas params from where
1015− NoHaving :: HavingClause outer commons 'Ungrouped schemas params from
545+data HavingClause tables grouping params where
546+ NoHaving :: HavingClause tables 'Ungrouped params
1016547 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)
548+ :: [Condition tables ('Grouped bys) params]
549+ -> HavingClause tables ('Grouped bys) params
550+deriving instance Show (HavingClause tables grouping params)
551+deriving instance Eq (HavingClause tables grouping params)
552+deriving instance Ord (HavingClause tables grouping params)
1022553
1023554-- | 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 <$> conditions)
1030−
1031−-- | A `CommonTableExpression` is an auxiliary statement in a `with` clause.
1032−data CommonTableExpression statement
1033− (schemas :: SchemasType)
1034− (params :: [NullityType])
1035− (commons0 :: FromType)
1036− (commons1 :: FromType) where
1037− CommonTableExpression
1038− :: Aliased (statement commons schemas params) (cte ::: common)
1039− -> CommonTableExpression statement schemas params commons (cte ::: common ': commons)
1040−instance
1041− ( KnownSymbol cte
1042− , commons1 ~ (cte ::: common ': commons)
1043− ) => Aliasable cte
1044− (statement commons schemas params common)
1045− (CommonTableExpression statement schemas params commons commons1) where
1046− statement `as` cte = CommonTableExpression (statement `as` cte)
1047−instance
1048− ( KnownSymbol cte
1049− , commons1 ~ (cte ::: common ': commons)
1050− ) => Aliasable cte
1051− (statement commons schemas params common)
1052− (Path (CommonTableExpression statement schemas params) commons commons1) where
1053− statement `as` cte = csingleton (statement `as` cte)
555+renderHavingClause :: HavingClause tables grouping params -> ByteString
556+renderHavingClause = \case
557+ NoHaving -> ""
558+ Having [] -> ""
559+ Having conditions ->
560+ " HAVING" <+> commaSeparated (renderExpression <$> conditions)
1054561
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
562+{-----------------------------------------
563+Sorting
564+-----------------------------------------}
1074565
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
566+-- | `SortExpression`s are used by `sortBy` to optionally sort the results
567+-- of a `Query`. `Asc` or `Desc` set the sort direction of a `NotNull` result
568+-- column to ascending or descending. Ascending order puts smaller values
569+-- first, where "smaller" is defined in terms of the `.<` operator. Similarly,
570+-- descending order is determined with the `.>` operator. `AscNullsFirst`,
571+-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to
572+-- determine whether nulls appear before or after non-null values in the sort
573+-- ordering of a `Null` result column.
574+data SortExpression tables grouping params where
575+ Asc
576+ :: Expression tables grouping params ('Required ('NotNull ty))
577+ -> SortExpression tables grouping params
578+ Desc
579+ :: Expression tables grouping params ('Required ('NotNull ty))
580+ -> SortExpression tables grouping params
581+ AscNullsFirst
582+ :: Expression tables grouping params ('Required ('Null ty))
583+ -> SortExpression tables grouping params
584+ AscNullsLast
585+ :: Expression tables grouping params ('Required ('Null ty))
586+ -> SortExpression tables grouping params
587+ DescNullsFirst
588+ :: Expression tables grouping params ('Required ('Null ty))
589+ -> SortExpression tables grouping params
590+ DescNullsLast
591+ :: Expression tables grouping params ('Required ('Null ty))
592+ -> SortExpression tables grouping params
593+deriving instance Show (SortExpression tables grouping params)
594+
595+-- | Render a `SortExpression`.
596+renderSortExpression :: SortExpression tables grouping params -> ByteString
597+renderSortExpression = \case
598+ Asc expression -> renderExpression expression <+> "ASC"
599+ Desc expression -> renderExpression expression <+> "DESC"
600+ AscNullsFirst expression -> renderExpression expression
601+ <+> "ASC NULLS FIRST"
602+ DescNullsFirst expression -> renderExpression expression
603+ <+> "DESC NULLS FIRST"
604+ AscNullsLast expression -> renderExpression expression <+> "ASC NULLS LAST"
605+ DescNullsLast expression -> renderExpression expression <+> "DESC NULLS LAST"