Question

I have three tables (admin,domain,user) as shown below

• ‘admin'(admin_id, email, domain_id, pass)
• ‘domain'(domain_id, name)
• ‘user’ (user_id, email, domain_id, pass)

Admin table:

+--------------------------------+         
| admin_id | email | domain_id  |          
+--------------------------------+         
| 1        | aaa   | 2034       |        
| 2        | bbb   | 3034       |
| 3        | ccc   | 2034       | 
+--------------------------------+

User table

+--------------------------------+         
| user_id | email | domain_id  |          
+--------------------------------+         
| 11        | aaa   | 2034       |        
| 12        | bbb   | 3034       |
| 13        | ccc   | 2034       | 
| 15        | ddd   | 2034       | 
| 16        | eee   | 3034       |
+--------------------------------+

Domain table:

+-----------------------+         
| domain_id | name    |          
+-----------------------+         
| 2034      | aaa.com |        
| 3034      | bbb.com |
+-----------------------+

Output:

+------------+
|[e-mail] |
|[e-mail] |
+------------+

So i want records from user table which are not present in admin table.

Is there any way to this without NOT IN query?

Answer 1

Is there any way to this without NOT IN query?

Yes, using LEFT JOIN of user with admin.

If id attribute in user and admin tables is used to decide if the two records belong to the same user, then your LEFT JOIN would be on this attribute, as follows:

SELECT CONCAT(u.email, CONCAT('@', d.name))
FROM 
    user u
    JOIN domain d
    ON u.domain_id = d.domain_id
    LEFT JOIN admin a
    ON u.id = a.id
WHERE 
    a.id IS NULL

If id attribute alone is not enough and you need domain_id as well to decide that two records belong to the same user, then

SELECT CONCAT(u.email, CONCAT('@', d.name))
FROM 
    user u
    JOIN domain d
    ON u.domain_id = d.domain_id
    LEFT JOIN admin a
    ON u.id = a.id AND u.domain_id = a.domain_id
WHERE 
    a.id IS NULL

Edit:

As per your update to the question, since email and domain are shared by both admin and user tables, you should LEFT JOIN these tables on those two columns:

SELECT CONCAT(u.email, CONCAT('@', d.name))
FROM 
    user u
    JOIN domain d
    ON u.domain_id = d.domain_id
    LEFT JOIN admin a
    ON u.email = a.email AND u.domain_id = a.domain_id
WHERE 
    a.email IS NULL