I would like to add functionality to an application where if a user selects something in a drop down then I will filter by that value, but if the user clears the drop down then I will get everything. I have decided to do this using a LIKE clause in a Stored Proc where I will have a parameter set either to the exact value (if selected) or to % (if cleared). My question is: 1. Does SQL Server see the LIKE '%' and ignore the filter or will it still attempt to filter, even though all results will be returned? 2. If an exact value is used with no wilcard characters (LIKE 'Michael') will SQL Server treat it as a = (which I assume will be faster than a LIKE), and also use the index on the name field? 3. Do the same rules apply to MySql?