Re: where clause + function, execution order

Julius Tuskenis <julius@xxxxxxxx> · Fri, 11 Nov 2011 17:54:00 +0200



    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..
    

    -- 

      Julius Tuskenis

      Head of the programming department

      UAB nSoft

      mob. +37068233050