• I don't know about DAC being on a list of tools to master. Agree with others about DTA not being on it... I've seen DTA (and the missing indexes dmv's) suggest new indexes, where adding a column to an existing index would handle the query... I think all they know is to add a new one.

    Wayne
    Microsoft Certified Master: SQL Server 2008
    Author - SQL Server T-SQL Recipes


    If you can't explain to another person how the code that you're copying from the internet works, then DON'T USE IT on a production system! After all, you will be the one supporting it!
    Links:
    For better assistance in answering your questions
    Performance Problems
    Common date/time routines
    Understanding and Using APPLY Part 1 & Part 2