Question

Say i have 2 tables, person and job.

+--------+--------------+------+-----+---------+----------------+
| Field  | Type         | Null | Key | Default | Extra          |
+--------+--------------+------+-----+---------+----------------+
| id     | int(11)      | NO   | PRI | NULL    | auto_increment |
| name   | varchar(255) | NO   |     | NULL    |                |
| job_id | int(11)      | NO   |     | NULL    |                |
+--------+--------------+------+-----+---------+----------------+

+----------+--------------+------+-----+---------+----------------+
| Field    | Type         | Null | Key | Default | Extra          |
+----------+--------------+------+-----+---------+----------------+
| j_id     | int(11)      | NO   | PRI | NULL    | auto_increment |
| j_name   | varchar(255) | NO   |     | NULL    |                |
| j_active | tinyint(1)   | NO   |     | 0       |                |
+----------+--------------+------+-----+---------+----------------+

How would i do a select where it only returns a job_id where j_active = 1 and otherwise return 0 or NULL? So, I would want to always return all persons but when their job isn’t active i dont want to return their job id

Answer 1

select * from person p left join job j on p.job_id=j.j_id and j.j_active=1