SQL Server Clustered Index - Order of Index Question

Question

I have a table like so:

keyA keyB data

keyA and keyB together are unique, are the primary key of my table and make up a clustered index.

Answer 1

Just in case this isn't obvious: the sort order of your index does not promise much about the the sort order of the results in a query.

In your queries, you must still add an

ORDER BY KeyA, KeyB

or

ORDER BY KeyB, KeyA

The optimizer may be pleased to find the data already physically ordered in the index as desired and save some time, but every query that is supposed to deliver data in a particular order must have an ORDER BY clause at the end of it. Without an order by, SQL Server makes no promises with respect to the order of a recordset, or even that it will come back in the same order from query to query.