This insanely cool new performance-related update is one of nicest features in SQL Server 2019, and certainly one I’ve been looking forward to for a long time.
If you’ve done any work around performance tuning and user-defined scalar functions, I’m pretty sure you’ll love this.
Scalar functions can be a real headache when you’re performance tuning. For one, they don’t parallelize. In fact, if you use a scalar function in a computed column, it will prevent any query that uses that table from going parallel – even if you don’t reference that column at all!
I wish the DATEDIFF() function would count the number of working days (mondays through fridays) between two dates for me, but until that happens, I’ve had to roll my own scalar function. I tried to think of a smart way involving perhaps a modulus calculation, but I quickly succumbed to a more down-to-earth approach.
Here’s a handy conversion tool that I built for myself in order to convert semi-colon delimited data (very common in files, etc) into a table. It comes in the form of a scalar function, that converts a varchar(max) to an XML value.
A while ago, I needed to create a URL encoding function in T-SQL. URL encoding is what happens when you translate special characters (basically anything that isn’t an alphanumerical) so they’ll fit in a URL.