MySQL query from 2 tables confusion

Question

I have a query that I would like to run but is not returning the expected results.

So my tables are like this

users (has two columns)
user_id,name

users_archive (has the same two columns) 
user_id,name

I want to basically run a query that lists user_id from the respective table where the username matches what I'm searching for

For my example I have a user called MikeBOSS in users_archive with an user_id of 123 (there is no MikeBOSS in users table)

SELECT users.user_id, users_archive.user_id 
FROM users 
LEFT JOIN users_archive ON users_archive.name='MikeBOSS' 
WHERE users.name='MikeBOSS';

but that returns no results

SELECT users.user_id, users_archive.user_id 
FROM users, users_archive 
WHERE (users.name='MikeBOSS' OR users_archive.name='MikeBOSS');

That returns a bunch of results from the users table that are incorrect.

Could someone maybe point me in the correct direction?

Answer 1

You do not want a JOIN, you want a UNION. Look

SELECT users.user_id, 'users'
FROM users 
WHERE users.name='MikeBOSS'
UNION 
SELECT users_archive.user_id, 'archive'
FROM users_archive
WHERE users_archive.name='MikeBOSS';

Answer 2

A join condition normally links two tables. Yours does not:

ON users_archive.name='MikeBOSS' 

A join condition that does link the two tables might look something like:

ON users.name = users_archive.name

If you wonder about the number of rows this returns, check each table individually. Is there even a row with name = 'MikeBoss' in the users_archive table?

Answer 3

Change

SELECT users.user_id, users_archive.user_id 
FROM users 
LEFT JOIN users_archive ON users_archive.name='MikeBOSS' 
WHERE users.name='MikeBOSS';

To

SELECT users.user_id, users_archive.user_id 
FROM users 
LEFT JOIN users_archive ON users.name = users_archive.name WHERE users.name='MikeBOSS';

Answer 4

May be this could work if you have no relation between 2 tables. Using left join gives you record from one table even if its not present in other.

SELECT users.user_id, users_archive.user_id 
FROM users 
LEFT JOIN users_archive ON users.userid = users_archive.userid and users.name = users_archive.name
WHERE users.name='MikeBOSS';