No offense, but it sounds as though your database isn't very well designed:
not knowing which of 50 tables something could be in doesn't sound right!

Are the 50 tables identical, except for one thing? For instance, do you have
one table for each department in a company, or one for each product that's
sold, or something like that? Odds are you should have a single table with
one additional field to distinguish that additional dimension.