RegexSplit() is a table-valued function that lets you split a string into pieces using a specified regular expression. RegexSplit() is a SQL CLR table-valued function that exposes the System.Text.RegularExpressions' Split() method.
Let's look at a few examples, inspired by another handy Regular Expressions tutorial
Let's split a string into words
declare @regex_pattern varchar(max) = '\s+'
select *
from dbo.RegexSplit('How do I split an arbitrary string into words?', @regex_pattern)
select *
from dbo.RegexSplit('Does this work if the words are oddly-formed?', @regex_pattern)