Gerald Nowitzky wrote: > > Hello! > I have got a question about the performance of the "group by" > clause. I am > running SAPDB 7.4.3.14 on W2K. > my query > > select x,y from zipcodes where country_id='D' group by y,x > order by y,x > > with SAPDB runs about 1.100 msec on a given hardware, and > just 160 msec with > MS-SQL. > the problem seems to be the grouping of the result. without > the grouping > SAPDB is 50 msec. > > There is an Index on Y,X on table zipcodes. This helps a lot > for sorting, > but not for the grouping. > > Any hints how to speed this up?? > Thanks a lot! > (Gerald)
In your case the easiest way is to throw the group-by-clause away because it does nothing. A little bit more earnest: if grouping and ordering has to be done with the same values, the extra order-by-clause can be thrown away. It is as you said, index on x,y will not help for grouping. No, there is no 'how-to-speed-up-this' in general. Elke SAP Labs Berlin _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
