Count of other rows in table with the same value

Question

So I\'m a bit new to mySQL and can figure out how to do this. I have a table with columns for worker, the building they work in, and the office they work in.

I\'m tr

Answer 1

Try this:

SELECT t1.*,
  (SELECT COUNT(1)
  FROM mytable t2
  WHERE t2.`room number` = t1.`room number`
  )
FROM mytable t1

I advice you don't use field name with white space, use the underscore instead white space.