Commit 8d338894 authored by Ian Foote's avatar Ian Foote Committed by Tim Graham
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[1.8.x] Fixed #24925 -- Document using Coalesce on MySQL 

Add warning for using Coalesce with python values on MySQL and document
workaround.

Backport of 14dead04 from master
parent 2aa65460

docs/ref/models/database-functions.txt

+11 −0
Original line number Diff line number Diff line
@@ -55,6 +55,17 @@ Usage examples:: 
    >>> print(aggregated['combined_age_default'])

    None



.. warning::



    A python value passed to ``Coalesce`` on MySQL may be converted to an

    incorrect type unless explicitly cast to the correct database type:



    >>> from django.db.models.expressions import RawSQL

    >>> from django.utils import timezone

    >>> now = timezone.now()

    >>> now_sql = RawSQL("cast(%s as datetime)", (now,))

    >>> Coalesce('updated', now_sql)



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