FIRST_VALUE

Parameters

column

Column or expression whose value is returned

PARTITION BYoptional

Columns that split rows into partitions

ORDER BYoptional

Order of rows in the partition that defines which row is first

framekeywordoptional

Window frame: ROWS, RANGE or GROUPS BETWEEN start AND end; by default, with ORDER BY, from the start of the partition to the current row together with rows equal to it in ORDER BY, without ORDER BY, the whole partition

Return value

A value of the same type as column

Examples

SELECT member_name,
	status,
	birthday,
	FIRST_VALUE(member_name) OVER (
		PARTITION BY status
		ORDER BY birthday
	) AS oldest_in_status
FROM FamilyMembers;

SELECT family_member,
	date,
	unit_price,
	unit_price - FIRST_VALUE(unit_price) OVER (
		PARTITION BY family_member
		ORDER BY date
	) AS diff_from_first
FROM Payments
ORDER BY family_member,
	date;

Details

See also

Where to learn

• Types of window functions
• Window Frames, RANGE and ROWS