Question

I tried looking for a question such as this on SO but a lot of them were outer joins with more complicated select clauses whereas my question is more simple and should be a faster reference for newbies at MySQL.

Being used to Oracle SQL, I was trying to join three tables and perform a delete like so:

DELETE * FROM tbl_login, tbl_profile, images
WHERE tbl_login.loginid = tbl_profile.loginid
AND tbl_profile.loginid = images.loginid
AND loginid = 'derek';

In MySQL my attempt is:

DELETE FROM tbl_profile, images, tbl_login
USING tbl_profile INNER JOIN images INNER JOIN tbl_login
WHERE tbl_profile.loginid = images.loginid 
AND images.loginid = tbl_login.loginid
AND loginid='derek';

I ran this in the SQL section of PHPMyadmin and it told me that loginid was ambiguous which I thought was funny because if I’m joining the three tables why would it be ambiguous? So I edited it and made it

tbl_login.loginid = 'derek' 

that deleted the correct row from the tbl_login table but it ended up deleting all the rows from my other tables. What am I doing wrong here?

Answer 1

I think your query should look something like this (note the different way the join conditions are defined):

DELETE FROM tbl_profile, images, tbl_login
USING tbl_profile INNER JOIN images ON images.loginid = tbl_profile.loginid
INNER JOIN tbl_login ON tbl_login.loginid = tbl_profile.loginid
WHERE tbl_login.loginid='derek';

I assume you want to delete the rows from all 3 tables. If you only want to delete from tbl_login, the previous answer tells you how to do it 🙂