Having Clause 

Create Table

CREATE TABLE employees (

    emp_no INT PRIMARY KEY,

    emp_name VARCHAR(50),

    designation VARCHAR(50),

    designation_no INT,

    sal DECIMAL(10, 2),

    commission DECIMAL(10, 2)

);

//Insert Records

INSERT INTO employees (emp_no, emp_name, designation, designation_no, sal, commission) VALUES

(1, 'XYZ', 'Manager', NULL, 5000.00, 1000.00),

(2, 'PQR', 'Developer', 1, 4000.00, NULL),

(3, 'ABC', 'Salesperson', 2, 3000.00, 500.00),

(10, 'XYZ', 'Manager', NULL, 5000.00, 1000.00),

(12, 'XYZ', 'Manager', NULL, 5000.00, 1000.00),

(13, 'XYZ', 'Manager', NULL, 5000.00, 1000.00),

(101, 'John Doe', 'Manager', 1, 75000.00, 5000.00),

(102, 'Jane Smith', 'Executive', 2, 60000.00, 3000.00),

(103, 'Richard Roe', 'HR Officer', 3, 50000.00, 2000.00),

(104, 'Mary Major', 'Accountant', 4, 55000.00, 2500.00),

(105, 'James Junior', 'IT Specialist', 5, 70000.00, 4000.00),

(106, 'ABC', 'IT Specialist', 5, 55555.00, 333.00),

(107, 'PQR', 'IT Specialist', 5, 755555.00, 7333.00);

Output :

+--------+--------------+---------------+----------------+-----------+------------+

| emp_no | emp_name     | designation   | designation_no | sal       | commission |

+--------+--------------+---------------+----------------+-----------+------------+

|      1 | XYZ          | Manager       |           NULL |   5000.00 |    1000.00 |

|      2 | PQR          | Developer     |              1 |   4000.00 |       NULL |

|      3 | ABC          | Salesperson   |              2 |   3000.00 |     500.00 |

|     10 | XYZ          | Manager       |           NULL |   5000.00 |    1000.00 |

|     12 | XYZ          | Manager       |           NULL |   5000.00 |    1000.00 |

|     13 | XYZ          | Manager       |           NULL |   5000.00 |    1000.00 |

|    101 | John Doe     | Manager       |              1 |  75000.00 |    5000.00 |

|    102 | Jane Smith   | Executive     |              2 |  60000.00 |    3000.00 |

|    103 | Richard Roe  | HR Officer    |              3 |  50000.00 |    2000.00 |

|    104 | Mary Major   | Accountant    |              4 |  55000.00 |    2500.00 |

|    105 | James Junior | IT Specialist |              5 |  70000.00 |    4000.00 |

|    106 | ABC          | IT Specialist |              5 |  55555.00 |     333.00 |

|    107 | PQR          | IT Specialist |              5 | 755555.00 |    7333.00 |

+--------+--------------+---------------+----------------+-----------+------------+

select COUNT(sal) as avg,emp_name from employee group by emp_name having emp_name="XYZ";

Output :

+-----+----------+

| avg | emp_name |

+-----+----------+

|   4 | XYZ      |

+-----+----------+

1 row in set (0.00 sec)