No, i didn't compared the execution plans between SQL Server Express and SQL Pro but it's a pretty good idea.

Thank's for your help

The auto-close is turned-off. It's not a problem cause by opening or closing a database. The test have being done with the using the application itself and in Sql Server...

1. Do you mean tables "Indexes". If you mean "indexes" instead of indices : for the Table1 it's DrID and in Table2 it's ResponseID which is not included in...