Today I finished my presentation about finding a unified algorithm for Relational Division, which should work for all types of division; singlerecord and multirecord, singlecolumn and multicolumn and both exact division and with remainder.
Optionally it should work with single and multiple divisor sets. That's 16 permutations of relational division kinds.
A bonus point is that the algorithm I've found work across multiple platforms with standard SQL language elements.
Also, I have performance tested the algorithm with the sample data from Mr Celko here.
For such small sample set, my algorithm is in the top queries, but the real performance kicks in when you...