Tom Lane-2 wrote > Pavel Stehule < > pavel.stehule@
> > writes: >> I was informed about impossibility to use a polymorphic functions >> together >> with domain types > >> see > >> create domain xx as numeric(15); > >> create or replace function g(anyelement, anyelement) >> returns anyelement as >> $$ select $1 + $2 $$ >> language sql immutable; > >> postgres=# select g(1::xx, 2::xx); >> ERROR: return type mismatch in function declared to return xx >> DETAIL: Actual return type is numeric. >> CONTEXT: SQL function "g" during inlining > > That example doesn't say you can't use polymorphic functions with domains. > It says that this particular polymorphic function definition is wrong: > it is not making sure its result is of the expected data type. I don't > recall right now whether SQL functions will apply an implicit cast on the > result for you, but even if they do, an upcast from numeric to some domain > over numeric wouldn't be implicit. How would that be possible though? Since any number of domains could be defined over numeric as soon as the "+" operator causes the domain to be lost there is no way to get it back manually - you cannot just make it "SELECT ($1 + $2)::xx". Does something like: SELECT ($1 + $2)::$1%TYPE exist where you can explicitly cast to the type of the input argument? David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/polymorphic-SQL-functions-has-a-problem-with-domains-tp5798349p5798356.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
