Re: ISAM calls/second

Scott Black wrote: > > I have the following two queries: (HP-UX 10.20, OnLine 7.22) > > select sum(price * quantity) expdate > from podetail, pomaster > where pomaster.number = podetail.number > and expdate between "01/01/97" and "12/31/97" > and chgcode = "5065"; > > select sum(price * quantity) expdate_odate > from podetail, pomaster > where pomaster.number = podetail.number > and expdate between "01/01/97" and "12/31/97" > or (expdate is null > and odate between "01/01/97" and "12/31/97") > and chgcode = "5065"; > > as you can see the second one is the same as the first except if expdate > is null then drive on odate instead. Um, I don't think so. I think what you have in the second one is: select everything from the first one, PLUS any records where expdateis null and odate in 1997; you're missing a pair of parentheses: select sum(price * quantity) expdate_odate from podetail, pomaster where pomaster.number = podetail.number and (expdate between "01/01/97" and "12/31/97" or (expdate is null and odate between "01/01/97" and "12/31/97" ) ) and chgcode = "5065"; AND has precedence over OR. Without parens, your OR will probably cause a sequential scan. What did your set explain output say? -- June ---- June Tong Informix Software ---- ---- Senior Consultant (650) 926-6140 ---- ---- International Support junet@informix.com ---- ---- Location-du-jour: Menlo Park ----