On Wed, Jun 21, 2006 at 03:47:19PM +0200, nicky wrote: > WHERE substr(t0.code,1,2) not in ('14','15','16','17') > AND (substr(t0.correctie,4,1) <> '1' OR t0.correctie is null) > AND EXTRACT(YEAR from t1.datum) > 2004; How much data do you expect to be getting back from that where clause? Unless you plan on inserting most of the table, some well-placed indexes would probably help, and fixing the datum portion might as well (depending on how far back the data goes). Specifically: CREATE INDEX t0_code_partial ON t0(substr(code,1,2)); (yeah, I know t0 is an alias, but I already snipped the table name) and AND t1.datum >= '1/1/2005' (might need to cast that to a date or whatever). -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461