index question

[John Mancuso]

If I have 2 large tables A and B and I need to join them:
 
select * from A,B where A.col1=B.col1
 
If A.col1 is an index and B.col1 is not, if I create an index on B.col1
will this index be used? In other words how are indexes used on table
joins?
 
Thanks
 
John Mancuso
Linux Administrator/MySQL DBA
IT Infrastructure
American Home Mortgage
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