Using subselect to accomplish LEFT JOIN

Question

Is is possible to accomplish the equivalent of a LEFT JOIN with subselect where multiple columns are required. Here's what I mean.

SELECT m.*, (SELECT * FROM model WHERE id = m.id LIMIT 1) AS models FROM make m

As it stands now doing this gives me a 'Operand should contain 1 column(s)' error.

Yes I know this is possible with LEFT JOIN, but I was told it was possible with subselect to I'm curious as to how it's done.

Answer 1

A subselect can only have one column returned from it, so you would need one subselect for each column that you would want returned from the model table.

Answer 2

There are many practical uses for what you suggest.

This hypothetical query would return the most recent release_date (contrived example) for any make with at least one release_date, and null for any make with no release_date:

SELECT m.make_name, 
       sub.max_release_date
  FROM make m
       LEFT JOIN 
           (SELECT id, 
                   max(release_date) as max_release_date
              FROM make 
           GROUP BY 1) sub
       ON sub.id = m.id