Safe Haskell	None
Language	Haskell2010

Rel8.Internal.Window

Synopsis

newtype Window a b = Window (Windows a b)
data Partition a
over :: Window a b -> Partition a -> Window a b
partitionBy :: EqTable b => (a -> b) -> Partition a
orderPartitionBy :: Order a -> Partition a

Documentation

newtype Window a b Source #

Window is an applicative functor that represents expressions that contain window functions. window can be used to evaluate these expressions over a particular query.

Constructors

Window (Windows a b)

Instances

Instances details

ProductProfunctor Window Source #
Instance details Defined in Rel8.Internal.Window Methods purePP :: b -> Window a b (**) :: Window a (b -> c) -> Window a b -> Window a c empty :: Window () () (*!) :: Window a b -> Window a' b' -> Window (a, a') (b, b')
Profunctor Window Source #
Instance details Defined in Rel8.Internal.Window Methods dimap :: (a -> b) -> (c -> d) -> Window b c -> Window a d lmap :: (a -> b) -> Window b c -> Window a c rmap :: (b -> c) -> Window a b -> Window a c (#.) :: forall a b c q. Coercible c b => q b c -> Window a b -> Window a c (.#) :: forall a b c q. Coercible b a => Window b c -> q a b -> Window a c
Applicative (Window a) Source #
Instance details Defined in Rel8.Internal.Window Methods pure :: a0 -> Window a a0 # (<>) :: Window a (a0 -> b) -> Window a a0 -> Window a b # liftA2 :: (a0 -> b -> c) -> Window a a0 -> Window a b -> Window a c # (>) :: Window a a0 -> Window a b -> Window a b # (<*) :: Window a a0 -> Window a b -> Window a a0 #
Functor (Window a) Source #
Instance details Defined in Rel8.Internal.Window Methods fmap :: (a0 -> b) -> Window a a0 -> Window a b # (<$) :: a0 -> Window a b -> Window a a0 #
Apply (Window a) Source #
Instance details Defined in Rel8.Internal.Window Methods (<.>) :: Window a (a0 -> b) -> Window a a0 -> Window a b (.>) :: Window a a0 -> Window a b -> Window a b (<.) :: Window a a0 -> Window a b -> Window a a0 liftF2 :: (a0 -> b -> c) -> Window a a0 -> Window a b -> Window a c

data Partition a Source #

In PostgreSQL, window functions must specify the "window" or "partition" over which they operate. The syntax for this looks like: SUM(salary) OVER (PARTITION BY department). The Rel8 type Partition represents everything that comes after OVER.

Partition is a Monoid, so Windows created with partitionBy and orderWindowBy can be combined using <>.

Instances

Instances details

Contravariant Partition Source #
Instance details Defined in Rel8.Internal.Window Methods contramap :: (a' -> a) -> Partition a -> Partition a' # (>$) :: b -> Partition b -> Partition a #
Monoid (Partition a) Source #
Instance details Defined in Rel8.Internal.Window Methods mempty :: Partition a # mappend :: Partition a -> Partition a -> Partition a # mconcat :: [Partition a] -> Partition a #
Semigroup (Partition a) Source #
Instance details Defined in Rel8.Internal.Window Methods (<>) :: Partition a -> Partition a -> Partition a # sconcat :: NonEmpty (Partition a) -> Partition a # stimes :: Integral b => b -> Partition a -> Partition a #

over :: Window a b -> Partition a -> Window a b infixl 1 Source #

over adds a Partition to a Window expression.

  cumulative (sum . salary) over partitionBy department <> orderPartitionBy (salary >$< desc)

partitionBy :: EqTable b => (a -> b) -> Partition a Source #

Restricts a window function to operate only the group of rows that share the same value(s) for the given expression(s).

orderPartitionBy :: Order a -> Partition a Source #

Controls the order in which rows are processed by window functions. This does not need to match the ordering of the overall query.