Select statement from tables which have now been split

Question

I used to select from 3 tables:
user, login, location
I would do:
select distinct user.id, login.computer_id, location.id as location_id
from user, login, location
where user.id = login.user_id
and login.location_id = location.id
and user.id = "manny"
but user has now been split into user1, and user2
I want to pull data where it exists from user1 or user2.
Much of the data in user1 is duplicated in user2 and vice versa, but I want to pull only one instance where it appears so that I can still get single row results of:
ID COMPUTER_ID LOCATION_ID
mannyd redstar_1 Bronx, NY
Any ideas on the query?

Answer 1

Why would you split a single table into multiple tables with the same structure and much of the same data? That seems rather counterproductive.
I suppose you could do something like
select user.id, login.computer_id, location.id as location_id
from user1 user, login, location
where user.id = login.user_id
and login.location_id = location.id
and user.id = 'manny'
UNION
select user.id, login.computer_id, location.id as location_id
from user2 user, login, location
where user.id = login.user_id
and login.location_id = location.id
and user.id = 'manny'but that's obviously going to be much more expensive than the single-table approach...
Justin