Re: count(*), EXISTS, indexes

>   CREATE TABLE A (x int PRIMARY KEY, real v);
>   CREATE TABLE B (x int);
>
> I'd like to calculate:
>
>   SELECT sum(v) FROM A WHERE EXISTS (SELECT 1 FROM B WHERE A.x=B.x);

This seems to be a reasonably-performing workaround:
 SELECT DISTINCT x INTO TEMP C FROM A,B WHERE A.x=B.x; SELECT sum(v) FROM A,C WHERE A.x=C.x;

-- 
Itai Zukerman  <http://www.math-hat.com/~zukerman/>