question about results where i dont have a match

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....


example table

accountnumber optionskey
1111                        1004
2222                        1005

select * from billing where optionskey in ('1004', '1005', '1006')
I would like to know that there was no hit for an optionskey of '1006'

any ideas