873c511 · squeal · git.iko.soy

git.iko.soy/squeal

window functions - attempt 3

commit873c5111afcf27ce863e359ccf7722bc6076f13f authorEitan Chatav <eitan.chatav@gmail.com> dateThu 10 Jan 2019, 19:44 (8 years ago) parent7b9b2af

2 files changed+165−55

compare with dev

unifiedsplit

squeal-postgresql/src/Squeal/PostgreSQL/Expression.hs+149 squeal-postgresql/src/Squeal/PostgreSQL/Query.hs+16−55

squeal-postgresql/src/Squeal/PostgreSQL/Expression.hs+149

@@ -16,11 +16,13 @@ Squeal expressions are the atoms used to build statements.

1616 , FlexibleContexts

1717 , FlexibleInstances

1818 , FunctionalDependencies

19+ , GADTs

1920 , GeneralizedNewtypeDeriving

2021 , LambdaCase

2122 , MagicHash

2223 , OverloadedStrings

2324 , ScopedTypeVariables

25+ , StandaloneDeriving

2426 , TypeApplications

2527 , TypeFamilies

2628 , TypeInType

@@ -141,6 +143,18 @@ module Squeal.PostgreSQL.Expression

141143 , count, countDistinct

142144 , every, everyDistinct

143145 , max_, maxDistinct, min_, minDistinct

146+ -- * Window Functions

147+ , WindowDefinition (..)

148+ , partitionBy

149+ , WindowFunction (..)

150+ , rank

151+ , rowNumber

152+ , denseRank

153+ , percentRank

154+ , cumeDist

155+ -- * Sorting

156+ , SortExpression (..)

157+ , OrderBy (..)

144158 -- * Types

145159 , TypeExpression (..)

146160 , PGTyped (..)

@@ -1778,3 +1792,138 @@ instance PGTyped schemas ty

17781792instance (KnownNat n, PGTyped schemas ty)

17791793 => PGTyped schemas (nullity ('PGfixarray n ty)) where

17801794 pgtype = fixarray @n (pgtype @schemas @ty)

1795+

1796+{-----------------------------------------

1797+Sorting

1798+-----------------------------------------}

1799+

1800+-- | `SortExpression`s are used by `sortBy` to optionally sort the results

1801+-- of a `Query`. `Asc` or `Desc` set the sort direction of a `NotNull` result

1802+-- column to ascending or descending. Ascending order puts smaller values

1803+-- first, where "smaller" is defined in terms of the `.<` operator. Similarly,

1804+-- descending order is determined with the `.>` operator. `AscNullsFirst`,

1805+-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to

1806+-- determine whether nulls appear before or after non-null values in the sort

1807+-- ordering of a `Null` result column.

1808+data SortExpression commons schemas params grp from where

1809+ Asc

1810+ :: Expression commons schemas params grp from ('NotNull ty)

1811+ -> SortExpression commons schemas params grp from

1812+ Desc

1813+ :: Expression commons schemas params grp from ('NotNull ty)

1814+ -> SortExpression commons schemas params grp from

1815+ AscNullsFirst

1816+ :: Expression commons schemas params grp from ('Null ty)

1817+ -> SortExpression commons schemas params grp from

1818+ AscNullsLast

1819+ :: Expression commons schemas params grp from ('Null ty)

1820+ -> SortExpression commons schemas params grp from

1821+ DescNullsFirst

1822+ :: Expression commons schemas params grp from ('Null ty)

1823+ -> SortExpression commons schemas params grp from

1824+ DescNullsLast

1825+ :: Expression commons schemas params grp from ('Null ty)

1826+ -> SortExpression commons schemas params grp from

1827+deriving instance Show (SortExpression commons schemas params grp from)

1828+

1829+class OrderBy expr where

1830+ orderBy

1831+ :: [SortExpression commons schemas params grp from]

1832+ -> expr commons schemas params grp from

1833+ -> expr commons schemas params grp from

1834+

1835+-- | Render a `SortExpression`.

1836+instance RenderSQL (SortExpression commons schemas params grp from) where

1837+ renderSQL = \case

1838+ Asc expression -> renderSQL expression <+> "ASC"

1839+ Desc expression -> renderSQL expression <+> "DESC"

1840+ AscNullsFirst expression -> renderSQL expression

1841+ <+> "ASC NULLS FIRST"

1842+ DescNullsFirst expression -> renderSQL expression

1843+ <+> "DESC NULLS FIRST"

1844+ AscNullsLast expression -> renderSQL expression <+> "ASC NULLS LAST"

1845+ DescNullsLast expression -> renderSQL expression <+> "DESC NULLS LAST"

1846+

1847+data WindowDefinition commons schemas params grp from where

1848+ WindowDefinition

1849+ :: SListI bys

1850+ => NP (Expression commons schemas params grp from) bys

1851+ -> [SortExpression commons schemas params grp from]

1852+ -> WindowDefinition commons schemas params grp from

1853+

1854+instance OrderBy WindowDefinition where

1855+ orderBy sortsR (WindowDefinition parts sortsL)

1856+ = WindowDefinition parts (sortsL ++ sortsR)

1857+

1858+instance RenderSQL (WindowDefinition commons schemas from grp params) where

1859+ renderSQL (WindowDefinition part ord) =

1860+ renderPartitionByClause part <> renderOrderByClause ord

1861+ where

1862+ renderPartitionByClause = \case

1863+ Nil -> ""

1864+ parts -> "PARTITION" <+> "BY" <+> renderCommaSeparated renderExpression parts

1865+ renderOrderByClause = \case

1866+ [] -> ""

1867+ srts -> " ORDER" <+> "BY"

1868+ <+> commaSeparated (renderSQL <$> srts)

1869+

1870+partitionBy

1871+ :: SListI bys

1872+ => NP (Expression commons schemas params grp from) bys

1873+ -> WindowDefinition commons schemas params grp from

1874+partitionBy bys = WindowDefinition bys []

1875+

1876+newtype WindowFunction

1877+ (commons :: FromType)

1878+ (schemas :: SchemasType)

1879+ (params :: [NullityType])

1880+ (grp :: Grouping)

1881+ (from :: FromType)

1882+ (ty :: NullityType)

1883+ = UnsafeWindowFunction { renderWindowFunction :: ByteString }

1884+ deriving (GHC.Generic,Show,Eq,Ord,NFData)

1885+

1886+instance RenderSQL (WindowFunction commons schemas params grp from ty) where

1887+ renderSQL = renderWindowFunction

1888+

1889+{- | rank of the current row with gaps; same as `rowNumber` of its first peer

1890+>>> :{

1891+let

1892+ expr :: WindowExpression commons schemas params 'Ungrouped '["tab" ::: '["a" ::: ty]] ('NotNull 'PGint8)

1893+ expr = rank `Over` (partitionBy #a)

1894+in

1895+ printSQL expr

1896+:}

1897+rank() OVER (PARTITION BY "a")

1898+-}

1899+rank :: WindowFunction commons schemas from grp params ('NotNull 'PGint8)

1900+rank = UnsafeWindowFunction "rank()"

1901+

1902+{- | number of the current row within its partition, counting from 1

1903+>>> printSQL rowNumber

1904+row_number()

1905+-}

1906+rowNumber :: WindowFunction commons schemas from grp params ('NotNull 'PGint8)

1907+rowNumber = UnsafeWindowFunction "row_number()"

1908+

1909+{- | rank of the current row without gaps; this function counts peer groups

1910+>>> printSQL denseRank

1911+dense_rank()

1912+-}

1913+denseRank :: WindowFunction commons schemas from grp params ('NotNull 'PGint8)

1914+denseRank = UnsafeWindowFunction "dense_rank()"

1915+

1916+{- | relative rank of the current row: (rank - 1) / (total partition rows - 1)

1917+>>> printSQL percentRank

1918+percent_rank()

1919+-}

1920+percentRank :: WindowFunction commons schemas from grp params ('NotNull 'PGfloat8)

1921+percentRank = UnsafeWindowFunction "percent_rank()"

1922+

1923+{- | cumulative distribution: (number of partition rows

1924+preceding or peer with current row) / total partition rows

1925+>>> printSQL cumeDist

1926+cume_dist()

1927+-}

1928+cumeDist :: WindowFunction commons schemas from grp params ('NotNull 'PGfloat8)

1929+cumeDist = UnsafeWindowFunction "cume_dist()"

squeal-postgresql/src/Squeal/PostgreSQL/Query.hs+16−55

@@ -74,7 +74,6 @@ module Squeal.PostgreSQL.Query

7474 , where_

7575 , groupBy

7676 , having

77− , orderBy

7877 , limit

7978 , offset

8079 -- * From Clauses

@@ -92,8 +91,6 @@ module Squeal.PostgreSQL.Query

9291 , By (..)

9392 , GroupByClause (..)

9493 , HavingClause (..)

95− -- * Sorting

96− , SortExpression (..)

9794 -- * Subquery Expressions

9895 , in_

9996 , rowIn

@@ -412,6 +409,11 @@ data Selection commons schemas params grp from row where

412409 :: Selection commons schemas params grp from right

413410 -> Selection commons schemas params grp from left

414411 -> Selection commons schemas params grp from (Join left right)

412+ Over

413+ :: SListI row

414+ => NP (Aliased (WindowFunction commons schemas params grp from)) row

415+ -> WindowDefinition commons schemas params grp from

416+ -> Selection commons schemas params grp from row

415417instance (KnownSymbol col, row ~ '[col ::: ty])

416418 => Aliasable col

417419 (Expression commons schemas params grp from ty)

@@ -444,6 +446,15 @@ instance RenderSQL (Selection commons schemas params grp from row) where

444446 Star -> "*"

445447 DotStar tab -> renderSQL tab <> ".*"

446448 Also right left -> renderSQL left <> ", " <> renderSQL right

449+ Over winFns winDef ->

450+ let

451+ renderOver

452+ :: Aliased (WindowFunction commons schemas params grp from) field

453+ -> ByteString

454+ renderOver winFn = renderAliased renderSQL winFn

455+ <+> "OVER" <+> parenthesized (renderSQL winDef)

456+ in

457+ renderCommaSeparated renderOver winFns

447458

448459-- | the `TableExpression` in the `select` command constructs an intermediate

449460-- virtual table by possibly combining tables, views, eliminating rows,

@@ -662,13 +673,8 @@ having

662673having hv rels = rels

663674 { havingClause = case havingClause rels of Having hvs -> Having (hv:hvs) }

664675

665−-- | An `orderBy` is an endomorphism of `TableExpression`s which appends an

666−-- ordering to the right of the `orderByClause`.

667−orderBy

668− :: [SortExpression commons schemas params grp from] -- ^ sort expressions

669− -> TableExpression commons schemas params grp from

670− -> TableExpression commons schemas params grp from

671−orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}

676+instance OrderBy TableExpression where

677+ orderBy srts rels = rels {orderByClause = orderByClause rels ++ srts}

672678

673679-- | A `limit` is an endomorphism of `TableExpression`s which adds to the

674680-- `limitClause`.

@@ -1035,51 +1041,6 @@ instance RenderSQL (HavingClause commons schemas params grp from) where

10351041 Having conditions ->

10361042 " HAVING" <+> commaSeparated (renderSQL <$> conditions)

10371043

1038−{-----------------------------------------

1039−Sorting

1040−-----------------------------------------}

1041−

1042−-- | `SortExpression`s are used by `sortBy` to optionally sort the results

1043−-- of a `Query`. `Asc` or `Desc` set the sort direction of a `NotNull` result

1044−-- column to ascending or descending. Ascending order puts smaller values

1045−-- first, where "smaller" is defined in terms of the `.<` operator. Similarly,

1046−-- descending order is determined with the `.>` operator. `AscNullsFirst`,

1047−-- `AscNullsLast`, `DescNullsFirst` and `DescNullsLast` options are used to

1048−-- determine whether nulls appear before or after non-null values in the sort

1049−-- ordering of a `Null` result column.

1050−data SortExpression commons schemas params grp from where

1051− Asc

1052− :: Expression commons schemas params grp from ('NotNull ty)

1053− -> SortExpression commons schemas params grp from

1054− Desc

1055− :: Expression commons schemas params grp from ('NotNull ty)

1056− -> SortExpression commons schemas params grp from

1057− AscNullsFirst

1058− :: Expression commons schemas params grp from ('Null ty)

1059− -> SortExpression commons schemas params grp from

1060− AscNullsLast

1061− :: Expression commons schemas params grp from ('Null ty)

1062− -> SortExpression commons schemas params grp from

1063− DescNullsFirst

1064− :: Expression commons schemas params grp from ('Null ty)

1065− -> SortExpression commons schemas params grp from

1066− DescNullsLast

1067− :: Expression commons schemas params grp from ('Null ty)

1068− -> SortExpression commons schemas params grp from

1069−deriving instance Show (SortExpression commons schemas params grp from)

1070−

1071−-- | Render a `SortExpression`.

1072−instance RenderSQL (SortExpression commons schemas params grp from) where

1073− renderSQL = \case

1074− Asc expression -> renderSQL expression <+> "ASC"

1075− Desc expression -> renderSQL expression <+> "DESC"

1076− AscNullsFirst expression -> renderSQL expression

1077− <+> "ASC NULLS FIRST"

1078− DescNullsFirst expression -> renderSQL expression

1079− <+> "DESC NULLS FIRST"

1080− AscNullsLast expression -> renderSQL expression <+> "ASC NULLS LAST"

1081− DescNullsLast expression -> renderSQL expression <+> "DESC NULLS LAST"

1082−

10831044unsafeSubqueryExpression

10841045 :: ByteString

10851046 -> Expression commons schemas params grp from ty