Postgresql - INSERT RETURNING INTO ambiguous column reference

Question

Can someone politely explain this crazyness?

INSERT INTO "dbo"."UserProfile" ("FirstName")
VALUES('John')
RETURNING "UserProfileId" INTO _UserProfileId;

throws an ambiguous reference error, however this correctly executes:

INSERT INTO "dbo"."UserProfile" ("FirstName")
VALUES('John')
RETURNING "dbo"."UserProfile"."UserProfileId" INTO _UserProfileId;

_UserProfileId is a declared integer variable. I couldn't find any references to this syntax in the manual or why on earth this would be ambiguous in any way.

Answer 1

IN and OUT parameters (including columns in RETURNS TABLE) are visible inside every SQL command in the body of a plpgsql function.

If you have columns of the same name in your query, you have to table-qualify them to make it unambiguous. In your case, the table name would do:

... RETURNING "UserProfile"."UserProfileId" INTO _UserProfileId;

Details in the manual here.

Related:

• How to return result of a SELECT inside a function in PostgreSQL?
• Naming conflict between function parameter and result of JOIN with USING clause