Question about a user's login table

[cancer10]

HI

Here is a telephonic question that i was recently asked

When designing a table where the user's username and password are saved, apart from adding indexes to the columns, is there anything else that you should do so that when running a query like:

SELECT username FROM users WHERE username="abc" AND password="xyz"

the query does not scan the entire table?




Does anyone here knows the answer and tell me what is it?

Thanks

[sunfighter]

I believe a query always scans the entire table. How else would it find multiple listings?
If you don't care about multiple listings you could use LIMIT 1 to stop the search.