PHP & MySQL - How to delete a users records from two tables

Hello I'm new to PHP & MySQL and I was wondering how can I delete all of user_id 3 records from these two tables below using PHP & MySQL?

My MySQL tables


us table values

id skill_id user_id 9 7 3 10 8 3 11 9 3 12 10 3 13 17 6

ls table values

id skill experience self_grade date_created date_updated 7 html 5 years A 2010-10-19 07:11:08 2010-10-19 07:12:06 8 jquery 10 years B 2010-10-19 07:11:27 2010-10-19 07:12:06 9 css 1 year NULL 2010-10-19 07:11:38 2010-10-19 07:12:06 10 php 2 years C 2010-10-19 07:13:05 NULL 17 php 2 years C 2010-10-19 07:19:05 NULL


You could fetch all rows belonging to user_id = 3 and then build a DELETE statement with a generated WHERE clause.

But, however, I'm wondering if you have an inappropriate table design as you have a m:n relation between user and skill and you want to delete all skills the user with id 3 is related with. But this implicates a 1:m relation between user and skill (1 user has multiple skills, not sharing the skills with others). Or maybe I got something wrong...?

MySQL does support multi-table deletions, use:

FROM ls a
JOIN us b ON b.skill_id =
WHERE b.user_id = 3

Yes, you can use a multi-table DELETE statement, eg.

JOIN us ON us.skill_id =
WHERE ls.user_id = 3

Category:php Time:2010-10-19 Views:1
Tags: php mysql sql

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