Categories:
Aggregate Functions (General) , Window Functions (Analytic, Window Frame)

LAST_VALUE

Returns the last value within an ordered group of values.

See also:
FIRST_VALUE , NTH_VALUE

Syntax

LAST_VALUE( <expr> ) [ { IGNORE | RESPECT } NULLS ]
                     OVER ( [ PARTITION BY <expr1> ] ORDER BY <expr2> [ <window_frame> ] )

Usage Notes

  • For compatibility with implementations of this function in other systems, { IGNORE | RESPECT } NULLS can also be specified in the arguments for the function:

    LAST_VALUE( <expr> [ { IGNORE | RESPECT } NULLS ] ) OVER ...

  • If { IGNORE | RESPECT } NULLS is not specified, the default is RESPECT NULLS, i.e. a NULL value is returned if the expression contains a NULL value and it is the last value in the expression.

  • LAST_VALUE is an analytic function so it requires a window to be specified, consisting of the following elements:

    • PARTITION BY <expr1> subclause (optional).
    • ORDER BY <expr2> subclause (required) with an optional window_frame. For more details about additional supported ordering options (sort order, ordering of NULL values, etc.), see the ORDER BY query construct.
  • The optional window_frame (cumulative or sliding) specifies the subset of rows within the window for which the function is calculated. If no window_frame is specified, the default is the entire window:

    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING

    Note that this deviates from the ANSI standard, which specifies the following default for window frames:

    RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW

    For more details about window frames, including syntax and examples, see Window Frames.

Examples

SELECT
    column1,
    column2,
    LAST_VALUE(column2) OVER (PARTITION BY column1 ORDER BY column2) AS column2_last
FROM VALUES
    (1, 10), (1, 11), (1, 12),
    (2, 20), (2, 21), (2, 22);

+---------+---------+--------------+
| COLUMN1 | COLUMN2 | COLUMN2_LAST |
|---------+---------+--------------|
|       1 |      10 |           12 |
|       1 |      11 |           12 |
|       1 |      12 |           12 |
|       2 |      20 |           22 |
|       2 |      21 |           22 |
|       2 |      22 |           22 |
+---------+---------+--------------+