Reputation: 9148
Just for an example. How can I query my db to find two users who might be using the same phone number? I'm not inputting a specific number but I want to find all instances phone numbers that are being used more than once in the user table.
Upvotes: 2
Views: 979
Reputation: 2648
You would use two tables of the same table with aliasses like:
select a.name, b.name
from mytable a join mytable b on a.phonenumber = b.phonenumber
where a.name <> b.name
Upvotes: 0
Reputation: 562478
SELECT ... FROM users u1 JOIN users u2
ON u1.user_id <> u2.user_id AND u1.phone_number = u2.phone_number;
Upvotes: 5