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
beingdriveb by tableB and it is taking forever. Surely I must be able to force the system to read down tableB in
preferenceto 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
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