I don't know if Tom told you but your suggestion to see the real error code led my programmer to release a new version THAT WORKKED!!......I can not thank you enough.
-----Original Message----- From: Leyne, Sean <[email protected]> To: firebird-support <[email protected]> Sent: Mon, Apr 2, 2012 5:12 pm Subject: RE: [firebird-support] Not Exists cost > If B_TABLE.VALUE2 never contains 'X' and half of A_TABLE.VALUE1 are 'Y' > what would be the cost of executing this statement? A_TABLE.VALUE1 is > indexed and B_TABLE.VALUE2 does not have an index. > > Would it be half of A_TABLE rows times all of B_TABLE rows? Or would the > Not Exists statement be evaluated for every row in A_TABLE making it > A_TABLE rows times B_TABLE rows? > > SELECT * > FROM A_TABLE at > WHERE > at.VALUE1 = 'Y' AND > NOT EXISTS ( > SELECT 1 > FROM B_TABLE bt > WHERE bt.VALUE2 = 'X'); The query PLAN would tell you for certain, but I would expect the answer to be: half of A_TABLE rows times all of B_TABLE rows. Sean [Non-text portions of this message have been removed]
