Safe Haskell | None |
---|---|
Language | Haskell2010 |
Left, right, and full outer joins.
Opaleye.FunctionalJoin provides a much nicer, Haskelly, interface to joins than this module, which sticks to the (horrible) standard "make missing rows NULL" interface that SQL provides.
If you want inner joins, just use restrict
instead.
The use of the Default
typeclass means that the compiler will
have trouble inferring types. It is strongly recommended that you
provide full type signatures when using the join functions.
Example specialization:
leftJoin :: Select (Field a, Field b)
-> Select (Field c, FieldNullable d)
-> (((Field a, Field b), (Field c, FieldNullable d)) -> Field SqlBool
)
-> Select ((Field a, Field b), (FieldNullable c, FieldNullable d))
Synopsis
- leftJoin :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsR nullableFieldsR) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (fieldsL, nullableFieldsR)
- leftJoinA :: (Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsR nullableFieldsR) => Select fieldsR -> SelectArr (fieldsR -> Field SqlBool) nullableFieldsR
- rightJoin :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, fieldsR)
- fullJoin :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Default NullMaker fieldsR nullableFieldsR) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, nullableFieldsR)
- leftJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsR nullableFieldsR -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (fieldsL, nullableFieldsR)
- leftJoinAExplict :: Unpackspec fieldsR fieldsR -> NullMaker fieldsR nullableFieldsR -> Select fieldsR -> SelectArr (fieldsR -> Field SqlBool) nullableFieldsR
- rightJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsL nullableFieldsL -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, fieldsR)
- fullJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsL nullableFieldsL -> NullMaker fieldsR nullableFieldsR -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, nullableFieldsR)
- leftJoinInferrable :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsR nullableFieldsR, Map Nulled fieldsR ~ nullableFieldsR) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (fieldsL, nullableFieldsR)
- rightJoinInferrable :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Map Nulled fieldsL ~ nullableFieldsL) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, fieldsR)
- fullJoinInferrable :: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Default NullMaker fieldsR nullableFieldsR, Map Nulled fieldsL ~ nullableFieldsL, Map Nulled fieldsR ~ nullableFieldsR) => Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, nullableFieldsR)
Joins
:: (Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsR nullableFieldsR) | |
=> Select fieldsR | Right query |
-> SelectArr (fieldsR -> Field SqlBool) nullableFieldsR | Condition on which to join goes in, left join result comes out |
leftJoinA
is a convenient way of using left joins within arrow
notation
:: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Default NullMaker fieldsR nullableFieldsR) | |
=> Select fieldsL | Left query |
-> Select fieldsR | Right query |
-> ((fieldsL, fieldsR) -> Field SqlBool) | Condition on which to join |
-> Select (nullableFieldsL, nullableFieldsR) | Full outer join |
Explicit versions
leftJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsR nullableFieldsR -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (fieldsL, nullableFieldsR) Source #
leftJoinAExplict :: Unpackspec fieldsR fieldsR -> NullMaker fieldsR nullableFieldsR -> Select fieldsR -> SelectArr (fieldsR -> Field SqlBool) nullableFieldsR Source #
rightJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsL nullableFieldsL -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, fieldsR) Source #
fullJoinExplicit :: Unpackspec fieldsL fieldsL -> Unpackspec fieldsR fieldsR -> NullMaker fieldsL nullableFieldsL -> NullMaker fieldsR nullableFieldsR -> Select fieldsL -> Select fieldsR -> ((fieldsL, fieldsR) -> Field SqlBool) -> Select (nullableFieldsL, nullableFieldsR) Source #
Inferrable versions
:: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsR nullableFieldsR, Map Nulled fieldsR ~ nullableFieldsR) | |
=> Select fieldsL | Left query |
-> Select fieldsR | Right query |
-> ((fieldsL, fieldsR) -> Field SqlBool) | Condition on which to join |
-> Select (fieldsL, nullableFieldsR) | Left join |
:: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Map Nulled fieldsL ~ nullableFieldsL) | |
=> Select fieldsL | Left query |
-> Select fieldsR | Right query |
-> ((fieldsL, fieldsR) -> Field SqlBool) | Condition on which to join |
-> Select (nullableFieldsL, fieldsR) | Right join |
:: (Default Unpackspec fieldsL fieldsL, Default Unpackspec fieldsR fieldsR, Default NullMaker fieldsL nullableFieldsL, Default NullMaker fieldsR nullableFieldsR, Map Nulled fieldsL ~ nullableFieldsL, Map Nulled fieldsR ~ nullableFieldsR) | |
=> Select fieldsL | Left query |
-> Select fieldsR | Right query |
-> ((fieldsL, fieldsR) -> Field SqlBool) | Condition on which to join |
-> Select (nullableFieldsL, nullableFieldsR) | Full outer join |