在 sqlalchemy 中使用 sum 和 case 时出错

Question

I'm using sqlalchemy func.sum with case in a having condition but get below error. code:

query = query.having(
            func.sum(case([(e.c.escalation_type.in_(escalation_types), 1)], else_=0)) > 0
        )

escalation_types above is Python list get this error:

asyncpg.exceptions.UndefinedFunctionError: function sum(text) does not exist
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

Here is the SQL printed by above:

HAVING sum(CASE WHEN (escalation_1.escalation_type IN (:escalation_type_1)) THEN :param_1 ELSE :param_2 END) > :sum_1

what am I missing here? Thanks!

Answer 1

Looks like there is a bug in one of the libraries of sqlalchemy , asyncpg . I have to cast 1 and 0 to integer to make it work. here is working code:

query = query.having(
            func.sum(
                case(
                    [(e.c.escalation_type.in_(escalation_types), cast(1, Integer))],
                    else_=cast(0, Integer),
                )
            )
            > 0
        )