## Turing Machine in SQL (5/5)

This is the last of five posts on this subject.

In a previous post I have shown how to build a Turing Machine (TM) in SQL with Postgres using a recursive SQL function. I claimed that this would work with versions of Postgres older than 8.4. In this post, I actually investigate this claim, porting the script down to version 7.3 on a Debian Linux. Testing the relatively simple SQL script with older versions reminds us of all the goodies that have been added over the years.