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LAST_VALUE

Returns an expression evaluated at the last row of the window frame.

If there are no rows in the frame, returns NULL.

For an overview of window functions in SingleStoreDB, see Window Functions Guide.

Syntax

LAST_VALUE ( expression ) OVER (
    [PARTITION BY (col | expr), ...]
    [ORDER BY (col | expr), ...]
    [frame_clause]
)

Arguments

  • expression: any expression. This may be a column name, the result of another function, or a math operation.

Return Type

The result type of expression

Examples

CREATE TABLE example (a INT, b INT);

INSERT INTO example VALUES(1, 2), (2, 2), (3, 3), (4, 3);
CREATE TABLE tick_table(TIMESTAMP DATETIME(6), symbol VARCHAR(5), comp_name VARCHAR (30),   price NUMERIC(18,4));SELECT TIMESTAMP, symbol, price, MAX(price) OVER (PARTITION BY symbol) 
FROM tick_table GROUP BY TIMESTAMP;

INSERT INTO tick_table VALUES('2022-11-18 10:55:36.000000','STC','SomeTechCo', 100.00),
('2022-11-18 10:55:37.000000','STC','SomeTechCo', 102.00),
('2022-11-18 10:55:42.000000', 'STC', 'SomeTechCo', 105.00),
('2022-11-18 10:55:48.000000', 'STC', 'SomeTechCo', 101.00),
('2022-11-18 10:56:03.000000', 'STC', 'SomeTechCo', 99.00),
('2022-11-18 10:55:42.000000', 'AME', 'ACME', 198.00),
('2022-11-18 10:55:50.000000', 'AME', 'ACME', 208.00),
('2022-11-18 10:55:52.000000', 'AME', 'ACME', 210.00),
('2022-11-18 10:55:55.000000', 'AME', 'ACME', 211.00),
('2022-11-18 10:55:52.000000', 'OCO', 'OnCallCo', 21.00),
('2022-11-18 10:55:55.000000', 'OCO', 'OnCallCo', 22.00),
('2022-11-18 10:55:57.000000', 'OCO', 'OnCallCo', 21.00),
('2022-11-18 10:56:00.000000', 'OCO', 'OnCallCo', 23.00),
('2022-11-18 10:56:03.000000', 'OCO', 'OnCallCo', 24.00);

Window Function

SELECT a, LAST_VALUE(a) OVER(ORDER BY (a)) FROM example;

****
+------+----------------------------------+
| a    | LAST_VALUE(a) OVER(ORDER BY (a)) |
+------+----------------------------------+
|    1 |                                1 |
|    2 |                                2 |
|    3 |                                3 |
|    4 |                                4 |
+------+----------------------------------+

Window Frame Clause

SELECT a, LAST_VALE(a) OVER(ORDER BY (a) ROWS between 
CURRENT ROW and UNBOUNDED FOLLOWING) FROM example;

****
+------+---------------------------------------------------+
| a    | LAST_VALUE(a) OVER(ORDER BY (a)                   |
|      | ROWS between CURRENT ROW and UNBOUNDED FOLLOWING) |
+------+---------------------------------------------------+
|    1 |                                                 4 |
|    2 |                                                 4 |
|    3 |                                                 4 |
|    4 |                                                 4 |
+------+---------------------------------------------------+
SELECT TIMESTAMP, symbol, price, LAST_VALUE(price) OVER (
PARTITION BY symbol) FROM tick_table GROUP BY TIMESTAMP;

****
+----------------------------+--------+----------+------------------------+
| TIMESTAMP                  | symbol | price    | LAST_VALUE(price) OVER |
|                            |        |          | (PARTITION BY symbol)  |
+----------------------------+--------+----------+------------------------+
| 2022-11-18 10:55:42.000000 | AME    | 198.0000 |               208.0000 |
| 2022-11-18 10:55:55.000000 | AME    | 211.0000 |               208.0000 |
| 2022-11-18 10:55:50.000000 | AME    | 208.0000 |               208.0000 |
| 2022-11-18 10:55:52.000000 | OCO    |  21.0000 |                21.0000 |
| 2022-11-18 10:56:00.000000 | OCO    |  23.0000 |                21.0000 |
| 2022-11-18 10:55:57.000000 | OCO    |  21.0000 |                21.0000 |
| 2022-11-18 10:55:37.000000 | STC    | 102.0000 |                99.0000 |
| 2022-11-18 10:55:36.000000 | STC    | 100.0000 |                99.0000 |
| 2022-11-18 10:55:48.000000 | STC    | 101.0000 |                99.0000 |
| 2022-11-18 10:56:03.000000 | STC    |  99.0000 |                99.0000 |
+----------------------------+--------+----------+------------------------+