Category: T-SQL

Ginger Grant shows a couple of techniques for sampling from tables:

The random sample that TABLESAMPLE provides is based on the number of data pages, not the number of records. If you want the number of rows to be specifically limited you will need to use Top(n) as well. I’ve written all my samples based upon AdventureWorksDW so you can run them for yourself later. I’ve listed the variety of ways to call TABLESAMPLE and shown the number of records returned.

TABLESAMPLE is useful for spelunking, but is somewhat limited otherwise.

Michael Bourgon has a pivot script:

Say you have records from your monitor that happens to Track EventLogs.
We’ll call it EventLog_Tracking for argument’s sake (hint hint http://thebakingdba.blogspot.com/2015/05/powershell-eventlogtracking-capturing.html) and want to look at trends over time.

Dynamic pivoting is possible (I have an example en passant in a tally table presentation I created a couple years back), but it’s not the easiest thing in the world.