MySQL HAVING Clause

MySQL HAVING Clause is used with GROUP BY clause. It always returns the rows where condition is TRUE.

Syntax:

SELECT expression1, expression2, ... expression_n,   

aggregate_function (expression)  

FROM tables  

[WHERE conditions]  

GROUP BY expression1, expression2, ... expression_n  

HAVING condition;

Parameters

aggregate_function: It specifies any one of the aggregate function such as SUM, COUNT, MIN, MAX, or AVG.

expression1, expression2, … expression_n: It specifies the expressions that are not encapsulated within an aggregate function and must be included in the GROUP BY clause.

WHERE conditions: It is optional. It specifies the conditions for the records to be selected.

HAVING condition: It is used to restrict the groups of returned rows. It shows only those groups in result set whose conditions are TRUE.

HAVING Clause with SUM function

Consider a table “employees” table having the following data.

Here, we use the SUM function with the HAVING Clause to return the emp_name and sum of their working hours.

Execute the following query:

SELECT emp_name, SUM(working_hours) AS "Total working hours"  

FROM employees  

GROUP BY emp_name  

HAVING SUM(working_hours) > 5;

Simply, it can also be used with COUNT, MIN, MAX and AVG functions.