Re: [BUGS] No subselects in constraint (bug?) - Mailing list pgsql-sql

"Alexey V. Neyman" <avn@any.ru> writes:
> CREATE TABLE b (
>   int4 id
>   CHECK (id = ANY(SELECT a.id FROM a))
> );

> ERROR:  ExecEvalExpr: unknown expression type 108

More recent versions say

ERROR:  Cannot use subselect in CHECK clause

It seems to me that what you really want here is a foreign key
reference, anyway, not a handmade CHECK constraint.
        regards, tom lane