Safe Haskell	None
Language	Haskell2010

Opaleye.SQLite.Order

Synopsis

class PGOrd a
orderBy :: Order a -> Query a -> Query a
asc :: PGOrd b => (a -> Column b) -> Order a
desc :: PGOrd b => (a -> Column b) -> Order a
ascNullsFirst :: PGOrd b => (a -> Column b) -> Order a
descNullsLast :: PGOrd b => (a -> Column b) -> Order a
limit :: Int -> Query a -> Query a
offset :: Int -> Query a -> Query a
data Order a

Documentation

class PGOrd a Source #

Typeclass for Postgres types which support ordering operations.

Instances

Instances details

PGOrd PGCitext Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGTimestamptz Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGTimestamp Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGTime Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGText Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGNumeric Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGInt2 Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGInt4 Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGInt8 Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGFloat8 Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGFloat4 Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGDate Source #
Instance details Defined in Opaleye.SQLite.Order
PGOrd PGBool Source #
Instance details Defined in Opaleye.SQLite.Order

orderBy :: Order a -> Query a -> Query a Source #

Order the rows of a Query according to the Order.

import Data.Monoid (<>)

-- Order by the first column ascending.  When first columns are equal
-- order by second column descending.
example :: Query (Column PGInt4, Column PGText)
        -> Query (Column PGInt4, Column PGText)
example = orderBy (asc fst <> desc snd)

asc :: PGOrd b => (a -> Column b) -> Order a Source #

Specify an ascending ordering by the given expression. (Any NULLs appear last)

desc :: PGOrd b => (a -> Column b) -> Order a Source #

Specify an descending ordering by the given expression. (Any NULLs appear first)

ascNullsFirst :: PGOrd b => (a -> Column b) -> Order a Source #

Specify an ascending ordering by the given expression. (Any NULLs appear first)

descNullsLast :: PGOrd b => (a -> Column b) -> Order a Source #

Specify an descending ordering by the given expression. (Any NULLs appear last)

limit :: Int -> Query a -> Query a Source #

Limit the results of the given query to the given maximum number of items.

offset :: Int -> Query a -> Query a Source #

Offset the results of the given query by the given amount, skipping that many result rows.

data Order a Source #

An Order represents an expression to order on and a sort direction. Multiple Orders can be composed with mappend. If two rows are equal according to the first Order, the second is used, and so on.

Instances

Instances details

Contravariant Order Source #
Instance details Defined in Opaleye.SQLite.Internal.Order Methods contramap :: (a -> b) -> Order b -> Order a # (>$) :: b -> Order b -> Order a #
Divisible Order Source #
Instance details Defined in Opaleye.SQLite.Internal.Order Methods divide :: (a -> (b, c)) -> Order b -> Order c -> Order a # conquer :: Order a #
Decidable Order Source #
Instance details Defined in Opaleye.SQLite.Internal.Order Methods lose :: (a -> Void) -> Order a # choose :: (a -> Either b c) -> Order b -> Order c -> Order a #
Semigroup (Order a) Source #
Instance details Defined in Opaleye.SQLite.Internal.Order Methods (<>) :: Order a -> Order a -> Order a # sconcat :: NonEmpty (Order a) -> Order a # stimes :: Integral b => b -> Order a -> Order a #
Monoid (Order a) Source #
Instance details Defined in Opaleye.SQLite.Internal.Order Methods mempty :: Order a # mappend :: Order a -> Order a -> Order a # mconcat :: [Order a] -> Order a #