So you want people to be able to query your database, but you don't want there to be any performance penalty?  I'm afraid there's no such thing as a free...

You didn't specify any expected results based on the sample data you provided, so I'm just guessing here, but what happens if you change the outer join to an inner...

If he unticked it recently, is he still using the same query window?  He needs to open a new one for the change to take effect.  If that doesn't work,...

Ask him to go to Tools -> Options -> Query Execution -> ANSI and untick SET IMPLICIT_TRANSACTIONS.

John

You pay your money, you take your choice.  You could easily rewrite as follows - I don't think it would make any difference to performance either way.
...Field1...

This is a bigger subject than it's possible to cover in a forum topic, I'm afraid.  You need to read about which performance counters to capture, and how to capture...

Powershell will work, as will a SQLCMD script.  You can also run a single query against a group of registered servers.  For regular tasks, consider SSIS.  Thom is right -...

Next time this happens, don't restart SQL Server, because you'll lose all the metadata in your DMVs, which is invaluable for troubleshooting.  Make sure you establish a performance baseline and...

Kev

The second query has no WHERE clause, so you'll get one row in your result set for every row in the table.  The first query filters out rows...