As you may have seen in the SQL docs, we pass-through a lot of string related functions that Postgres supports

https://www.labkey.org/wiki/home/Documentation/page.view?name=labkeysql

However, we don't pass through regexp_matches(). I suspect this is because the return type of this function isn't a scalar value, but rather "setof text[]".

I don't know if you compile your own builds, but it would not be hard to create an method that wraps regexp_matches() with array_to_string(). see class OverlapsMethodInfo in Method.java