SQL Avg

The AVG function calculates the average (mean) of the numeric values in a column.

Calculating an average

AVG() divides the sum of a column by the number of non-NULL values in it, giving you the arithmetic mean. It is a fast way to answer questions like 'what does the typical employee earn?' without adding the numbers up by hand.

Average salary

SELECT AVG(salary) AS average_salary
FROM Employees;

Note: AVG ignores NULL values in both the total and the count. A row with a NULL salary does not drag the average down, because it is left out of the calculation entirely.

Rounding the result

An average often comes back with a long decimal tail. Wrapping AVG() in ROUND() keeps the output tidy. The second argument to ROUND controls how many decimal places to keep.

Average salary rounded to two decimals

SELECT ROUND(AVG(salary), 2) AS average_salary
FROM Employees;

Averages per group

As with the other aggregates, GROUP BY lets you compute a separate average for each category so you can compare, for example, the mean salary across departments.

Average salary by department

SELECT department, ROUND(AVG(salary), 2) AS avg_salary
FROM Employees
GROUP BY department;

Detail	Behavior
Input type	Numeric columns or expressions only
NULL handling	Excluded from both sum and count
Empty result	Returns NULL when no rows match
Common pairing	ROUND() for readable output, GROUP BY for per-category means

Note: Because NULLs are skipped, AVG(salary) is not always the same as SUM(salary) divided by COUNT(*). The count used by AVG only includes rows that actually have a value.

Keep Going

SQL Interview QuestionsPractice real questions asked for SQL Database Administrator SalarySee what Database Administrator roles pay in the market Auto Apply for JobsApply to open roles related to SQL and tweak your resume