lets say I have a table called "billing" that has thousands of accounts and then inside the billing table there is a column called optionskey. the column optionskey can be anyone of 100 numbers. 4 digits. this column corresponds to an optionskey table that describes the option.
ie... optionskey will translate to garbage... or water.
so I have a query with 200 possible options keys.
so I would run a query that says... select * from billing where optionskey in ('1001', 1002,'1115',etc....)
in the parenthesis, I want to supply it 200 optionkeys. I want to know which optionskeys are not in the table....
select * from billing where optionskey in ('1004', '1005', '1006')
I would like to know that there was no hit for an optionskey of '1006'