Work around for problems with Split function when connecting Tableau to PostgreSQL

I'm a big fan of the split function when doing calculated fields. Partly because far too often, the fields from the sources I work with are concatenations of other fields, or even because I've done a union of several CSV sources and some crucial bit of information is hidden in the table name/path. But recently I tried to use this with PostgreSQL and I got the following error

• ERROR: function split_part(text[], unknown, integer) does not exist; Error while executing the query

Now I could investigate this further on the PostgreSQL side of things but I just want to get my thing to work and move on. So instead here's the workaround I came up with:

mid([concat_str],start_of_split, find([concat_str],'/',start_of_split)-start_of_split)

where start_of_split is a fixed number of characters (maybe you want to do another find here) and '/' defines the delimiter to use when splitting.