Обсуждение: PLPGSQL problem with SELECT INTO

OK, I'm trying to count the number of records based on two criteria, this
works at the psql prompt but not in a plpgsql function

    SELECT count(*) FROM mytable WHERE fieldone = 'val1' AND fieldtwo =
'val2';

This gives me back '4' which is what I expect (trust me :)

but if I try to put this in a PLPGSQL function, it doesn't work.

    CREATE FUNCTION countRows (varchar, varchar) RETURNS int AS
'
    DECLARE
        val1 ALIAS FOR $1;
        val2 ALIAS FOR $2;
        total int;
    BEGIN
        SELECT INTO total count(*) FROM mytable WHERE fieldone =
val1 AND fieldtwo = val2;
        RETURN total;
    END;
    ' LANGUAGE PLPGSQL;


The value returned is much higher.  Actaully, it is exactly what the number
should be without the AND query.  No matter what I'. passing for the second
variable, I get the same result (even if it's a value not in that column
for any record)

Amy thoughts as to why this might be?

I'm using this in a procedure that will eventually delete certain rows from
a table and needs to decerement a field in another table based on how many
rows will be deleted?  Can I just do a DELETE and use GET DIAGNOSTICS to
get the number of rows that were deleted?

Take care,
Jay

> OK, I'm trying to count the number of records based on two criteria, this
> works at the psql prompt but not in a plpgsql function
>
>     SELECT count(*) FROM mytable WHERE fieldone = 'val1' AND fieldtwo
> =
> 'val2';
>
> This gives me back '4' which is what I expect (trust me :)
>
> but if I try to put this in a PLPGSQL function, it doesn't work.
>
>     CREATE FUNCTION countRows (varchar, varchar) RETURNS int AS
> '
>     DECLARE
>         val1 ALIAS FOR $1;
>         val2 ALIAS FOR $2;
>         total int;
>     BEGIN
>         SELECT INTO total count(*) FROM mytable WHERE fieldone =
> val1 AND fieldtwo = val2;
>         RETURN total;
>     END;
>     ' LANGUAGE PLPGSQL;


After some furtehr research I determined that it was ignoring the fieldTwo
check completely.  I finally narrowerd it ddown because my code read

    fieldTwo ALIAS FOR $2;

and the query read

    SELECT .....fieldtwo = fieldTwo

And plpgsql was not being case sensitive and thought it was comparing it to
itself.

Take care,
Jay

"Jay O'Connor" <joconnor@cybermesa.com> writes:
>     CREATE FUNCTION countRows (varchar, varchar) RETURNS int AS
> '
>     DECLARE
>         val1 ALIAS FOR $1;
>         val2 ALIAS FOR $2;
>         total int;
>     BEGIN
>         SELECT INTO total count(*) FROM mytable WHERE fieldone =
> val1 AND fieldtwo = val2;
>         RETURN total;
>     END;
>     ' LANGUAGE PLPGSQL;

> The value returned is much higher.  Actaully, it is exactly what the number
> should be without the AND query.  No matter what I'. passing for the second
> variable, I get the same result (even if it's a value not in that column
> for any record)

I kinda suspect you have an unexpected variable substitution.  Is the
above *exactly* how the offending function reads, or have you
editorialized on the names used?

            regards, tom lane

On 2003.05.29 14:41 Tom Lane wrote:

> I kinda suspect you have an unexpected variable substitution.  Is the
> above *exactly* how the offending function reads, or have you
> editorialized on the names used?

It was editorialized and in the editorializing I obscured the real issue.
I had a local variable name and a column name in my query as the same name,
differenitated only by case.  Unfortunately, plpgsql did not see them as
different :)

Take care,
Jay