In a legacy database (SQL Server 2000), we have a clustered index that looks like this:
CREATE CLUSTERED INDEX [IX_usr] ON [dbo].[usr]
(
[uid] ASC,
[ssn] ASC,
[lname] ASC
)
The thing is, as far as I know none of these fields are used together in a WHERE clause. Nor is there really any reason to use any of them together. Is there any reason to have a clustered index like this?