Re: BUG #6067: In PL/pgsql, EXISTS(SELECT ... INTO...) fails

Hello

2011/6/18 David Fetter <dfetter(at)vmware(dot)com>:
>
> The following bug has been logged online:
>
> Bug reference:      6067
> Logged by:          David Fetter
> Email address:      dfetter(at)vmware(dot)com
> PostgreSQL version: 9.0.4
> Operating system:   Linux
> Description:        In PL/pgsql, EXISTS(SELECT ... INTO...) fails
> Details:
>
> Here's some example code that reproduces the problem:
>
> CREATE OR REPLACE FUNCTION foo()
> RETURNS void
> LANGUAGE plpgsql
> AS $$
> DECLARE
>    i int;
> BEGIN
>    IF EXISTS (SELECT 1 INTO STRICT i) THEN
>        RAISE NOTICE '%', a;
>    END IF;
>    RETURN;
> END;
> $$;
> ERROR:  syntax error at or near "i"
> LINE 8:     IF EXISTS (SELECT 1 INTO STRICT i) THEN

You cannot to use PLpgSQL's addition "INTO" inside SQL statement. This
is not bug. INTO and STRICT are not SQL keywords, so they cannot be
used inside SQL expression.

Regards

Pavel Stehule

>                                            ^
>
> This came up in a case where there was an IF block that checked some
> conditions before checking whether there was a row.  If it found a row, it
> was supposed to use it in an EXCEPTION.  Instead, I had to do the query
> unconditionally, check the FOUND block in a separate nested IF statement,
> and generally uglify the code.
>
> Not everybody in IRC agreed that this is a bug, though.
>
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