Join sub-query. Query result is Maybe. The combinations of query and queryMaybe express inner joins, left outer joins, right outer joins, and full outer joins. Here is an example of a right outer join:

  outerJoin = relation $ do
    e <- queryMaybe employee
    d <- query department
    on $ e ?! E.deptId' .=. just (d ! D.deptId')
    return $ (,) |$| e |*| d

queryMaybe' :: (MonadQualify ConfigureQuery m, MonadQuery m) => Relation p r -> m (PlaceHolders p, Projection Flat (Maybe r)) Source

Join sub-query with place-holder parameter p. Query result is Maybe.

queryList :: MonadQualify ConfigureQuery m => Relation () r -> m (ListProjection (Projection c) r) Source

List sub-query, for IN and EXIST.

queryList' :: MonadQualify ConfigureQuery m => Relation p r -> m (PlaceHolders p, ListProjection (Projection c) r) Source

List sub-query, for IN and EXIST with place-holder parameter p.

queryScalar :: (MonadQualify ConfigureQuery m, ScalarDegree r) => UniqueRelation () c r -> m (Projection c (Maybe r)) Source

Scalar sub-query.

queryScalar' :: (MonadQualify ConfigureQuery m, ScalarDegree r) => UniqueRelation p c r -> m (PlaceHolders p, Projection c (Maybe r)) Source

Scalar sub-query with place-holder parameter p.

uniqueQuery' :: MonadQualifyUnique ConfigureQuery m => UniqueRelation p c r -> m (PlaceHolders p, Projection c r) Source

Join unique sub-query with place-holder parameter p.

uniqueQueryMaybe' :: MonadQualifyUnique ConfigureQuery m => UniqueRelation p c r -> m (PlaceHolders p, Projection c (Maybe r)) Source

Join unique sub-query with place-holder parameter p. Query result is Maybe.

Direct style join

type JoinRestriction a b = Projection Flat a -> Projection Flat b -> Projection Flat (Maybe Bool) Source

Restriction function type for direct style join operator.

rightPh :: Relation ((), p) r -> Relation p r Source

Simplify placeholder type applying left identity element.

leftPh :: Relation (p, ()) r -> Relation p r Source

Simplify placeholder type applying right identity element.

inner' infixl 8 Source

Arguments

:: Relation pa a	Left query to join
-> Relation pb b	Right query to join
-> [JoinRestriction a b]	Join restrictions
-> Relation (pa, pb) (a, b)	Result joined relation

Direct inner join with place-holder parameters.

left' infixl 8 Source

Arguments

:: Relation pa a	Left query to join
-> Relation pb b	Right query to join
-> [JoinRestriction a (Maybe b)]	Join restrictions
-> Relation (pa, pb) (a, Maybe b)	Result joined relation

Direct left outer join with place-holder parameters.

right' infixl 8 Source

Arguments

:: Relation pa a	Left query to join
-> Relation pb b	Right query to join
-> [JoinRestriction (Maybe a) b]	Join restrictions
-> Relation (pa, pb) (Maybe a, b)	Result joined relation

Direct right outer join with place-holder parameters.

full' infixl 8 Source

Arguments

:: Relation pa a	Left query to join
-> Relation pb b	Right query to join
-> [JoinRestriction (Maybe a) (Maybe b)]	Join restrictions
-> Relation (pa, pb) (Maybe a, Maybe b)	Result joined relation

Direct full outer join with place-holder parameters.

inner infixl 8 Source

Arguments

:: Relation () a	Left query to join
-> Relation () b	Right query to join
-> [JoinRestriction a b]	Join restrictions
-> Relation () (a, b)	Result joined relation

Direct inner join.

left infixl 8 Source

Arguments

:: Relation () a	Left query to join
-> Relation () b	Right query to join
-> [JoinRestriction a (Maybe b)]	Join restrictions
-> Relation () (a, Maybe b)	Result joined relation

Direct left outer join.

right infixl 8 Source

Arguments

:: Relation () a	Left query to join
-> Relation () b	Right query to join
-> [JoinRestriction (Maybe a) b]	Join restrictions
-> Relation () (Maybe a, b)	Result joined relation

Direct right outer join.

full infixl 8 Source

Arguments

:: Relation () a	Left query to join
-> Relation () b	Right query to join
-> [JoinRestriction (Maybe a) (Maybe b)]	Join restrictions
-> Relation () (Maybe a, Maybe b)	Result joined relation