Re: count record from two tables with duplicate check

You could try one of these queries. Actual performance depends on your table/index design:

SELECT (SELECT COUNT(EMP_NUM) FROM A WHERE NOT EXISTS (SELECT 'X' FROM B WHERE B.EMP_NUM = A.EMP_NUM))

	   +
	   (SELECT COUNT(EMP_NUM) FROM B) CNT

SELECT COUNT(*)
FROM (SELECT AAA

        FROM   (SELECT EMP_NUM AAA FROM A
                UNION ALL
                SELECT EMP_NUM AAA FROM B)
        GROUP BY AAA
	   ) X

sim Received on Wed Sep 14 2005 - 04:01:41 CDT