MySQL 'user_id' in where clause is ambiguous problem

Question

How can I correct the problem I keep getting from the code below which states \'user_id\' in where clause is ambiguous. Thanks for the help in advance.

Answer 1

You should be mention alias name of your column and assign to user_id like

SELECT user.*, user_info.* 
FROM user as u 
INNER JOIN user_info as ui ON u.user_id = ui.user_id
WHERE u.user_id='$user_id'