CaseStatement has no aggregate functions

[gitmalong]

How can I aggregate the SUM over the result of an CASE expression? I found there are no aggregate functions such as count or sum when building a CaseStatement.

https://docs.rs/sea-query/latest/sea_query/query/struct.CaseStatement.html

https://github.com/SeaQL/sea-query/pull/304/files#diff-8f5819aa8f1164e24c550b1dbe468b3fd76da938b9c19e8c17144d64ad463733R993

In plain postgres SQL I would do:

SUM(
     CASE WHEN years_passed IS NOT NULL
     THEN gain_loss ELSE CAST(0 AS DECIMAL) END
) 
AS my_val

[gitmalong]

I found I can make it work by wrapping Func::sum() around

[tyt2y3]

@gitmalong thanks for posting this. Would you mind posting the full snippet, that others might find useful?

Untested off my head:

Func::sum(Expr::case(..).finally(..))