>Is it better to use a JOIN or a SUBSELECT if either will produce the correct result?
>
>For example

>SELECT DISTINCT pol.agentcode,pol.ctrl_num,pol.incep_date FROM frpolicy pol;
>  JOIN frlocat loc ON pol.agentcode=loc.agentcode and pol.ctrl_num=loc.ctrl_num;
>  WHERE pol.incep_date >={8/31/2005} AND loc.state='OR'
>
>
>SELECT pol.agentcode,pol.ctrl_num,pol.incep_date FROM frpolicy pol;
> WHERE EXISTS (SELECT * FROM frlocat loc;
>                WHERE loc.agentcode=pol.agentcode
>                  AND loc.ctrl_num=pol.ctrl_num;
>                  AND loc.state="OR")
>   AND pol.incep_date >= {8/1/2005}
>

>
>produce identical results in approximately the same time.
>
>Is it a matter of style or is there a reason to use one rather than the other?
>
>Thanks......

If DISTINCT is necessary, then:
The second it is formally (in relational algebra) more correct,
infact the second can to be very more faster ( best case ) but little slower ( worst case )