The MySQL sum() function is used to return the total summed value of an expression.
SELECT SUM(aggregate_expression) FROM tables [WHERE conditions];
aggregate_expression: It specifies the column or expression that will be summed.
table_name: It specifies the tables, from where you want to retrieve records. There must be at least one table listed in the FROM clause.
WHERE conditions: It is optional. It specifies the conditions that must be fulfilled for the records to be selected.
Consider a table named "employees", having the following data.
Execute the following query:
SELECT SUM (working_hours) AS "Total working hours" FROM employees WHERE working_hours > 5;