It is fun to see how simple a subject interests us when working with SQL Server Performance Tuning. I believe SQL Server Performance Tuning is a very simple technique and I often discuss this with my clients during Comprehensive Database Performance Health Check. Today we are building a Collection of Articles that have recently generated interest on the blog as well as on the YouTube channel – SQL in Sixty Seconds.
The first video I build discusses how COUNT(*) uses the Indexes: COUNT(*) and Index – SQL in Sixty Seconds #175. Here I discuss how clustered and nonclustered index are chose by COUNT(*) operation.
In the response to the previous video, many asked if there will be a difference in performance Here is the second video I build COUNT(*) and COUNT(1): Performance Battle – SQL in Sixty Seconds #176.
Well, that’s it for today. If you liked this video, please do not forget to subscribe to my YouTube Channel – SQL in Sixty Seconds.
There were so many questions on these topics, and I have built Frequently Asked Questions here: COUNT(*) and Index Frequently Asked Questions.
Here are the previous two blog post, I strongly suggest you read them first before watching this video.
If you are looking forward to retrieving the row count of the table fastest possible way, I strongly suggest that you watch another video: Fastest Way to Retrieve Rowcount for a Table – SQL in Sixty Seconds #096
Many thought of using NOLOCK with COUN(*) or COUN(1), however, that is also not a good idea. Here is where I discuss why NOLOCK is not a good idea. Dirty Read with NOLOCK – SQL in Sixty Seconds #110
If you are in a fun mood, here is interesting puzzle: Solution – Puzzle – SELECT * vs SELECT COUNT(*)
Well, that’s it for today, I hope you enjoyed the COUNT(*) Collection of Articles.
Reference: Pinal Dave (http://blog.SQLAuthority.com)