Opaleye.Distinct

Documentation

distinct :: Default Distinctspec fields fields => Select fields -> Select fields

Remove duplicate rows from the Select.

Example type specialization:

distinct :: Select (Field a, Field b) -> Select (Field a, Field b)

Assuming the makeAdaptorAndInstance splice has been run for the product type Foo:

distinct :: Select (Foo (Field a) (Field b) (Field c)) -> Select (Foo (Field a) (Field b) (Field c))

If you want to run distinct on SelectArrs you should apply laterally to it:

laterally distinct :: Default Distinctspec fields fields => SelectArr i fields -> SelectArr i fields

data Distinctspec a b

Instances

Profunctor Distinctspec

Defined in Opaleye.Internal.Distinct

Methods

dimap :: (a -> b) -> (c -> d) -> Distinctspec b c -> Distinctspec a d

lmap :: (a -> b) -> Distinctspec b c -> Distinctspec a c

rmap :: (b -> c) -> Distinctspec a b -> Distinctspec a c

(#.) :: forall a b c q. Coercible c b => q b c -> Distinctspec a b -> Distinctspec a c

(.#) :: forall a b c q. Coercible b a => Distinctspec b c -> q a b -> Distinctspec a c

ProductProfunctor Distinctspec

Defined in Opaleye.Internal.Distinct

Methods

purePP :: b -> Distinctspec a b

(****) :: Distinctspec a (b -> c) -> Distinctspec a b -> Distinctspec a c

empty :: Distinctspec () ()

(***!) :: Distinctspec a b -> Distinctspec a' b' -> Distinctspec (a, a') (b, b')

SumProfunctor Distinctspec

Defined in Opaleye.Internal.Distinct

Methods

(+++!) :: Distinctspec a b -> Distinctspec a' b' -> Distinctspec (Either a a') (Either b b')

Default Distinctspec (Column a) (Column a)

Defined in Opaleye.Internal.Distinct

Methods

def :: Distinctspec (Column a) (Column a)

Default (WithNulls Distinctspec) a b => Default Distinctspec (MaybeFields a) (MaybeFields b)

Defined in Opaleye.Internal.Distinct

Methods

def :: Distinctspec (MaybeFields a) (MaybeFields b)

Functor (Distinctspec a)

Defined in Opaleye.Internal.Distinct

Methods

fmap :: (a0 -> b) -> Distinctspec a a0 -> Distinctspec a b

(<$) :: a0 -> Distinctspec a b -> Distinctspec a a0

Applicative (Distinctspec a)

Defined in Opaleye.Internal.Distinct

Methods

pure :: a0 -> Distinctspec a a0

(<*>) :: Distinctspec a (a0 -> b) -> Distinctspec a a0 -> Distinctspec a b

liftA2 :: (a0 -> b -> c) -> Distinctspec a a0 -> Distinctspec a b -> Distinctspec a c

(*>) :: Distinctspec a a0 -> Distinctspec a b -> Distinctspec a b

(<*) :: Distinctspec a a0 -> Distinctspec a b -> Distinctspec a a0

Explicit versions

distinctExplicit :: Distinctspec fields fields' -> Select fields -> Select fields'

Adaptors

distinctspecField :: Distinctspec (Column a) (Column a)

distinctspecMaybeFields :: WithNulls Distinctspec a b -> Distinctspec (MaybeFields a) (MaybeFields b)