What does SUM() do?

SQLJunior~1 min read

SUM() is an aggregate function that totals the values in a numeric column.

It adds up all the non-empty (NOT NULL) values and returns one total.

sql

SELECT SUM(salary)
FROM employees;

Returns the total of every employee's salary.

You can use it with GROUP BY to total by category:

sql

SELECT department, SUM(salary)
FROM employees
GROUP BY department;

Shows the salary total in each department.

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