depends what you mean. It's not 100% clear to me what you're getting at. you can use a subquery<BR><BR>UPDATE blah SET blah = blahblah WHERE somefield IN (SELECT something FROM somewhereelse)<BR><BR>is that what you mean?<BR>as for insert, I'm not seeing how the above could be a benefit.
in SQL Server you can build one big string (though rpeferably by an alternative concat method since scripted concatenation is very slow) and insert it at once, which can be more efficient than hitting the DB a lot. depends where the data's come from really.