My most recent Quizletter featured a quiz on ORDER BY in TSQL, complete with questions on the OFFSET and FETCH clauses which we got in SQL Server 2012.
One great thing about teaching TSQL School is that it reminds me of these cool options that can be easy to forget.
This week’s Quizletter featured a quiz on using the AVG() function in SQL Server.
I was inspired to write this quiz because I’ve been teaching “TSQL School” each week. When we covered aggregate functions, I remembered how tricksy AVG() can be.
Forgetfulness can lead to learning something new. This is a bit of a nightmare when it happens in production, but a treat when it happens in an isolated test system– and that’s how I learned this.
I left a bit of blocking open on my test VM, and forgot about it.
It’s tough to keep track of which features work in each version of SQL Server, and which Editions support them.
My memory told me that the new Adaptive Joins feature in SQL Server 2017 was Enterprise Edition only… and that’s correct, but I didn’t realize that the fancy new feature to make Multi-Statement TVFs smarter has much wider licensing.
The new Enterprise Automatic Tuning feature in SQL Server 2017 may sound intimidating at first – one question I get a lot lately is whether or not there’s a future for DBAs. Will Auto-Tune mean we don’t need any more human tuning?
Well, not anytime super soon.
I just spent 90 minutes of my life figuring out a detail about sys.dm_exec_query_stats which I’m pretty sure I figured out five years ago, but didn’t write a blog post about.
Time to write a blog post, so I can save time when I go searching for this in a couple years.
Most of the time in SQL Server, the MAX() function and a TOP(1) ORDER BY DESC will behave very similarly.
If you give them a rowstore index leading on the column in question, they’re generally smart enough to go to the correct end of the index, and – BOOP! – just pluck out the data you need without doing a big scan.
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