Explain Plan Shows a Cartesian Merge Join, How Would You Help?

December 24, 2010 Imagine that a developer approached you with the following SQL statement, and explained that he (or she) noticed that the execution plan showed a Cartesian merge join.  Even adding an ORDERED hint did not affect the execution plan, and the execution performance was the same with the ORDERED hint. SELECT X.TIME_PERIOD EXPOSURE_PERIOD,Y.TIME_PERIOD [...]