Mssql platform TOP and DISTINCT ordering issue

When doing a limit and a distinct query, DBAL generates an SQL statement in the form of SELECT TOP X DISTINCT, which SqlSrv does not like at all. Simply moving the the DISTINCT back to the start fixes this issue.

As far as I can see this is caused by the preg_replace in doModifyLimitQuery. Attached is a patch that makes it slightly more aware. There may be other phrases to check for, but none that I've come across yet.

Patch attached.