Hello everyone I must be doing something very wrong here so help please! I have two tables
tableA has 300,000 recs tableB has 20,000 recs I need to set the value of a field in table A to a value in table B depending on the existence of the record in table B. So what I have done is UPDATE tableA set a.val1=b.somefield FROM tableA a, tableB b WHERE a.key1=b.key1; The primary key of tableA is key1 and that of tableB is key1 ie the join is on primary keys. The "optimizer" has elected to d a sequential scan on tableA to determine which fields to update rather than the query being driveb by tableB and it is taking forever. Surely I must be able to force the system to read down tableB in preference to reading down tableA? (Please don't ask why tableA and tableB are not amalgamated - that's another story altogether!!!) Many thanks in advance Hilary Hilary Forbes The DMR Information and Technology Group (www.dmr.co.uk) Direct tel 01689 889950 Fax 01689 860330 DMR is a UK registered trade mark of DMR Limited ********************************************************** ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
