mirror of
https://github.com/khibino/haskell-relational-record.git
synced 2024-11-29 06:37:03 +03:00
44 lines
1.1 KiB
Haskell
44 lines
1.1 KiB
Haskell
{-# LANGUAGE TemplateHaskell, MultiParamTypeClasses, FlexibleInstances #-}
|
|
|
|
import Data.Int
|
|
|
|
import Database.Relational.Query
|
|
import Database.Relational.Query.TH
|
|
|
|
|
|
$(defineTable defaultConfig
|
|
"PUBLIC" "my_table"
|
|
[ ("person", [t| String |])
|
|
, ("family", [t| String |])
|
|
, ("age" , [t| Int32 |])
|
|
]
|
|
[] [0] (Just 0))
|
|
|
|
|
|
agesOfFamilies :: Relation () (String, Maybe Int32)
|
|
agesOfFamilies = aggregateRelation $ do
|
|
my <- query myTable
|
|
gFam <- groupBy $ my ! family' -- Specify grouping key
|
|
return $ gFam >< sum' (my ! age') -- Aggregated results
|
|
|
|
agesOfFamiliesO :: Relation () (String, Maybe Int32)
|
|
agesOfFamiliesO = aggregateRelation $ do
|
|
my <- query myTable
|
|
gFam <- groupBy $ my ! family'
|
|
let s = sum' (my ! age')
|
|
orderBy s Desc -- Only aggregated value is allowd to pass
|
|
orderBy gFam Asc
|
|
return $ gFam >< s
|
|
|
|
ageRankOfFamilies :: Relation () ((Int64, String), Int32)
|
|
ageRankOfFamilies = relation $ do
|
|
my <- query myTable
|
|
return $
|
|
rank `over` do
|
|
partitionBy $ my ! family' -- Monad to build window
|
|
orderBy (my ! age') Desc
|
|
><
|
|
my ! family'
|
|
><
|
|
my ! age'
|