In general, if you can do it with Prolog, you can do it with SQL... but should probably do it with Prolog.
> Note: Strictly speaking, this process is iteration not recursion, but RECURSIVE is the terminology chosen by the SQL standards committee.
That said, the feature was to some degree inspired by datalog.
EDIT: I should probably clarify, many dbmses probably have extensions that do make SQL turing complete, and the current standard is if you count stored procedures I guess. But CTEs themselves are more limited than what Prolog does.
This is actually not true. Behold, a cyclic tag system in SQL:2003-conformant SQL:
http://wiki.postgresql.org/wiki/Cyclic_Tag_System
Here's a blog diving into more detail: http://blog.coelho.net/database/2013/08/17/turing-sql-1.html
Although this is less strictly conforming.
The original thread was in the context of SQLite, which is trivially of equivalent computational power.
However, again: you should probably use Prolog.
I wish there was some nice off the shelf embed able FOSS DB like SQLite, but with datalog as a query language.