Michelle,

Actually, I think Bob's is the best:

select distinct a.id from a,b,c where a.id = b.id or a.id = c.id

You should add DISTINCT after SELECT if you don't want to get duplicate ID's for records in a that are in both b and c. My original suggestion will return the same results, but I think Bob's will be the fastest.

>>Now you have three :)
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>Yep. This place is great! I'm glad I've finally become a member.