3906bfb · squeal · git.iko.soy

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exists

3906bfbEitan Chatav8 years ago

squeal-postgresql/src/Squeal/PostgreSQL/Query.hs+20

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unifiedsplit

@@ -91,6 +91,7 @@ module Squeal.PostgreSQL.Query

91 , GroupByClause (..)

92 , HavingClause (..)

93 -- * Subquery Expressions

94+ , exists

94 , in_

95 , in_

95 , rowIn

96 , rowIn

96 , eqAll

97 , eqAll

@@ -321,6 +322,20 @@ let

321in printSQL query

322in printSQL query

322:}

323:}

323SELECT "col1" AS "col1", rank() OVER (PARTITION BY "col1" ORDER BY "col2" ASC) AS "rank" FROM "tab" AS "tab"

324SELECT "col1" AS "col1", rank() OVER (PARTITION BY "col1" ORDER BY "col2" ASC) AS "rank" FROM "tab" AS "tab"

325+

326+correlated subqueries

327+

328+>>> :{

329+let

330+ query :: Query '[] '[] (Public Schema) '[] '["col1" ::: 'NotNull 'PGint4]

331+ query =

332+ select #col1 (from (table (#tab `as` #t1))

333+ & where_ (exists (

334+ select Star (from (table (#tab `as` #t2))

335+ & where_ (#t2 ! #col2 .== #t1 ! #col1)))))

336+in printSQL query

337+:}

338+SELECT "col1" AS "col1" FROM "tab" AS "t1" WHERE EXISTS (SELECT * FROM "tab" AS "t2" WHERE ("t2"."col2" = "t1"."col1"))

324-}

339-}

325newtype Query

340newtype Query

326 (outer :: FromType)

341 (outer :: FromType)

@@ -1075,6 +1090,11 @@ unsafeRowSubqueryExpression

1075unsafeRowSubqueryExpression op xs q = UnsafeExpression $

1090unsafeRowSubqueryExpression op xs q = UnsafeExpression $

1076 renderSQL (row xs) <+> op <+> parenthesized (renderSQL q)

1091 renderSQL (row xs) <+> op <+> parenthesized (renderSQL q)

1077

1092

1093+exists

1094+ :: Query (Join outer from) commons schemas params row

1095+ -> Condition outer grp commons schemas params from

1096+exists query = UnsafeExpression $ "EXISTS" <+> parenthesized (renderSQL query)

1097+

1078-- | The right-hand side is a sub`Query`, which must return exactly one column.

1098-- | The right-hand side is a sub`Query`, which must return exactly one column.

1079-- The left-hand expression is evaluated and compared to each row of the

1099-- The left-hand expression is evaluated and compared to each row of the

1080-- sub`Query` result. The result of `in_` is `true` if any equal subquery row is found.

1100-- sub`Query` result. The result of `in_` is `true` if any equal subquery row is found.