Rick Baker's Personal Website

I work on so many sites, domains, linux boxes, MySQL servers, etc. that I have like a million and one passwords dancing around in my head. Went to add a database to an old devel box that I haven’t used for about 2 years and I couldn’t remember the MySQL root password. So I had to reset it. If anyone finds themselves in this situation, here’s how you do it if you have root access to the server. I’ll use my normal way of stopping/starting the service, you may need to alter this for your server.

/etc/init.d/mysql stop
mysqld --skip-grant-tables &
mysql (to get to MySQL shell)
mysql> update user set password = ('newpasssword') where user='root';
mysql> flush privileges;
mysql> exit;
/etc/init.d/mysql restart

Recently was asked a question on how to delete records from multiple tables with a single MySQL query. I’ll give an example below with one caveat. If your tables are INNODB and you have foreign keys then this query will fail. For INNODB you should just do a single delete and rely on the ON DELETE capabilities to handle any other deletes.

Anyways, so on to the query. Say you have 3 tables (table1, table2, and table3). Each of them have an entry for a variable that we’ll call $id and you want to delete from all 3 tables at once. Here you go:

delete t1, t2, t3
from table1 as t1
left join table2 as t2 on t2.id = t1.id
left join table3 as t3 on t3.id = t1.id
where t1.id = '$id'