String_Split Performance

Kevin Feasel



Aaron Bertrand looks into how STRING_SPLIT performs compared to other string splitting methods:

So with those limitations out in the open, we can move on to some performance testing. Given Microsoft’s track record with built-in functions that leverage CLR under the covers (coughFORMAT() cough), I was skeptical about whether this new function could come close to the fastest methods I’d tested to date.

Let’s use string splitters to separate comma-separated strings of numbers, this way our new friend JSON can come along and play too. And we’ll say that no list can exceed 8,000 characters, so no MAX types are required, and since they’re numbers, we don’t have to deal with anything exotic like Unicode.

The results are surprising.  I expected it to be somewhere around CLR-level, but not way better.

Related Posts


Kenneth Fisher explains a couple of database name functions in SQL Server: I’d never seen ORIGINAL_DB_NAME until recently and I thought it would be interesting to highlight it out, and in particular the difference between it and DB_NAME. I use DB_NAME and DB_ID fairly frequently in support queries (for example what database context is a query running from or what database are […]

Read More

Using STRING_AGG In SQL Server 2017

Derik Hammer talks about one of the nicer T-SQL additions in SQL Server 2017: Creating comma separated strings from a column, or delimited strings as I like to call it, is a very common problem in SQL. Beginning with SQL Server 2017 and Azure SQL Database, there is now another option to the existing set of solutions, STRING_AGG(). I […]

Read More


March 2016
« Feb Apr »