first_value.md

description
This section contains reference documentation for the FIRST_VALUE window function.

FIRST_VALUE

The FIRST_VALUE function returns the value from the first row in a window.

Signature

FIRST_VALUE(expression) [IGNORE NULLS | RESPECT NULLS] OVER ()

The default behavior is RESPECT NULLS. If the IGNORE NULLS option is specified, the function returns the first non-null row in each window (assuming one exists, null otherwise).

Example

This example computes the number of games played by a player in their first year.

SELECT playerName,
  yearID,
  numberOfGames,
  FIRST_VALUE(numberOfGames) OVER (
    PARTITION BY playerName
    ORDER BY yearID ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  )
FROM baseballStats;

Output:

playerName	yearID	numberOfGames	EXPR$3
p1	2000	10	10
p1	2001	15	10
p1	2002	12	10
p2	1990	120	120
p2	1991	124	120
p3	2006	30	30
p3	2007	25	30
p3	2009	20	30
p3	2010	15	30