SQL join ON not equal in Mysql

Question

I have two tables. Both contains question id field. I want to get all records from first table that are not present in second one. I don\'t want to use \"NOT IN\" constrain as s

Answer 1

Typically you would do this using a LEFT JOIN combined with a WHERE clause selecting every row where the joined table returns no results.

SELECT t1.*
FROM   Table1 t1
       LEFT OUTER JOIN Table2 t2 ON t2.ID = t1.ID
WHERE  t2.ID IS NULL