I know it's been a very long time since I posted anything, but I
felt the itch today. A question came up earlier this week at
work: How much is JOIN performance affected when using columns
that are not the exact same data type?
This is important for me because entity-attribute-value tables require a lot of self-joins. Let me start by saying that we mitigate one of the common drawbacks to EAVs - mashing diverse data types into a single column - by separating numeric, date, and character data into different tables. However, we mashed a lot of integer data …