We noticed that when we use some nested expression with distinctOnOrderBy like coalesce generates bad sql in the beginning of a query:
let someVal = coalesce [ entity1?.Entity1Value, entity2^.Entity2Value ]
distinctOnOrderBy [ asc someVal ] $ do pure someVal
gives something like that
SELECT DISTINCT ON (COALESCE("entity1"."entity2_value",)
COALESCE("entity1"."entity1_value", "entity2".entity2_value")
ORDER BY COALESCE("entity1"."entity1_value", "entity2".entity2_value") ASC
So it omits second substitution-part of COALESCE expression for some reasons but the value expression itself works perfectly in ORDER BY part. So it behaves badly only in DISTINCT ON (..) clause.
Rewriting it into usual distinctOn [don ...] $ do orderBy [...] works perfectly.
We noticed that when we use some nested expression with
distinctOnOrderBylikecoalescegenerates bad sql in the beginning of a query:gives something like that
So it omits second substitution-part of
COALESCEexpression for some reasons but the value expression itself works perfectly inORDER BYpart. So it behaves badly only inDISTINCT ON (..)clause.Rewriting it into usual
distinctOn [don ...] $ do orderBy [...]works perfectly.