Обсуждение: Concatenating String Literals in pgsql

How does one concat string literals in pgsql ?

The compiler complains about the concat operator in the following code
fragment:

RAISE EXCEPTION
    ''SELECT DISTINCT "t1"."usesysid" '' ||
        ''INTO userID '' ||
        ''FROM "pg_user" AS "t1" '' ||
        ''WHERE "t1"."usename" = current_user '' ||
        ''NOT FOUND'';

Thanks in advance.

Raymond

Raymond <support@bigriverinfotech.com> writes:
> The compiler complains about the concat operator in the following code
> fragment:

> RAISE EXCEPTION
>     ''SELECT DISTINCT "t1"."usesysid" '' ||
>         ''INTO userID '' ||

RAISE EXCEPTION doesn't support expressions in its arguments, IIRC.
The format has to be a simple string literal, and anything to be plugged
into it has to be a variable reference.

So, do the concatenation beforehand.

            regards, tom lane