mysql> select title, AVG(age)
-> from employee_data
-> GROUP BY title
-> HAVING AVG(age) > 30;
+----------------------------+----------+
| title | AVG(age) |
+----------------------------+----------+
| Customer Service Manager | 32.0000 |
| Finance Manager | 36.0000 |
| Multimedia Programmer | 36.0000 |
| Programmer | 30.5000 |
| Senior Marketing Executive | 36.0000 |
| Senior Programmer | 32.0000 |
| Senior Web Designer | 32.0000 |
| System Administrator | 34.5000 |
+----------------------------+----------+
8 rows in set (0.00 sec)