SQL - find records from one table which don't exist in another

Question

I\'ve got the following two SQL tables (in MySQL):

Phone_book
+----+------+--------------+
| id | name | phone_number |
+----+------+--------------+
| 1  | J         


        

Answer 1

The code below would be a bit more efficient than the answers presented above when dealing with larger datasets.

SELECT * FROM Call WHERE 
NOT EXISTS (SELECT 'x' FROM Phone_book where 
Phone_book.phone_number = Call.phone_number)