BruceS:
You have the functionality. Do a search an you will find that if returns things listed in variables.
I was thinking more like "YES" in a variable value
For example Sushi has a conveyors variable.
Query all sushi with conveyor = "yes"
or if other cats had the conyor variable,
Query all restaurants with conveyor = "yes"
The variables are more valueble for data analysis, because they require you to think when doing data entry, where if the instructions said "say there are converyor belts if there are conveyor belts" a non-mention may not be a no.