Re: count record from two tables with duplicate check

Seems like my first posting got lost. It's difficult to know which of the following sqls is the fastest. That depends on the design of your table (indexes) on the number of records on how up to date your statistics are and so on.

Nevertheless you could also try one of these:

SELECT COUNT(*)
FROM (SELECT AAA

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

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