Re: where clause + function, execution order

Hello,

On 2011.11.11 17:38, Sorin Dudui wrote:

Hi,

 

I have the following function:

 

===============================

CREATE OR REPLACE FUNCTION xxx(text)

  RETURNS SETOF vvvvv AS

$BODY$

select a.x, a.y,

    CASE

    WHEN strpos($1,b.x) > 0

    THEN b.x

    ELSE NULL

    END AS mp_hm

from  a LEFT JOIN  b ON a.id=b.id

 

                $BODY$

  LANGUAGE sql STABLE

  COST 1000

  ROWS 10000;

===============================

 

which I call as:

 

select * from xxx(‘test0|test1‘)  where a.x = ‘value’

You should get an error as there is no "a" in this statement...

 

 

I am wondering when the where clause (a.x = ‘value’) is executed. After the select statement in the function finishes? Or is it appended at the select statement in the function?

 

Function execute plan is prepared when creating it, so the "where" clause should check the function result not altering its execution..