When does a query use an Index?

I have looked through all the books I have and can't find a definitive answer.

1. Does a query use an Index when LIKE is used?
2. Does a query use an Index when an outer join is performed?
3. Does an Index get used when a view is used? The book says 'under certain conditions an Index will not be used' but doesn't say what they are.

Can anyone answer these please?

Thanks,

Andy Horne Received on Tue Sep 23 1997 - 00:00:00 CDT