The regression test file subselect.sql contains the following query under the
heading "Correlated subselects":
SELECT '' AS five, f1 AS "Correlated Field"
FROM SUBSELECT_TBL
WHERE (f1, f2) IN (SELECT f2, CAST(f3 AS int4) FROM SUBSELECT_TBL
WHERE f3 IS NOT NULL);
It has been pointed out to me that there is no correlation in this query. Is
there some other special purpose to this query or is it simply categorized
wrongly?
--
Peter Eisentraut
http://developer.postgresql.org/~petere/