On Wed, 2010-01-27 at 10:10 -0600, Les Mikesell wrote: > > I've seen mysql do some really stupid things, like a full 3-table join > into a (huge)disk temporary table when the select had a 'limit 10' and > was ordered by one of the fields that had an index. Very true. You can you use logic operations to build up "Tree Sets" as Temp Tables on disk and in RAM using Inner and Outer Joins and Index them the way you see fit. This I have done on Innodb. These methods work on many "List" types like Edge and Adjacency Modling. I did all the hard work on mssql then to innodb I went, which now was a big mistake. Basically it comes to a select, then the select gets built up into the rational you need of a temp table structure tree. John