How to Tune a SQL Statement

One of my standard questions I ask when interviewing a candidate with some database or SQL know how is:
Assume you have a fairly complex select statement operating on some serious tables (tens of millions of rows). The customer complains the SQL statement is to slow. What options would you consider for tuning such a select [...]

Building a Turing Engine in Oracle SQL using the Model Clause

Everybody who understands the working of a Turing machine and that of SQL understands, that SQL probably isn’t Turing complete, i.e. you can’t use it to build a Turing machine. Yet I’m going to show that you actually can implement a Turing Engine using Oracle SQL.
So for those among you who haven’t studied informatics: “What [...]