ABS

Returns the absolute value of a number.

PostgreSQL 17.9

ABS(num)

Return value

A non-negative number of the same type

PostgreSQL 17.9

SELECT ABS(-5.7);

abs
5.7

PostgreSQL 17.9

SELECT member_name,
	ABS(
		EXTRACT(
			YEAR
			FROM birthday
		) - 1980
	) AS years_from_1980
FROM FamilyMembers;

The distance between two numbers, regardless of which one is larger, is ABS(a - b).