Important

The SingleStore 9.1 release candidate (RC) is available now. It will be promoted to general availability (GA) soon and at that time it will be renamed to SingleStore 10.

In the interim, SingleStore 9.1 RC can be used to preview, evaluate, and provide feedback on the new and upcoming features in SingleStore 10, while SingleStore 9.0 is recommended for production workloads.

NTH_VALUE

Syntax

NTH_VALUE ( expression, n ) 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.
n: An integer or integer expression.

Return Type

The result type of the expression.

Examples

SQL

CREATE TABLE nth_example (a int, b int);

INSERT INTO nth_example VALUES (1, 2), (2, 2), (3, 3), (4, 3);

SQL

SELECT a, NTH_VALUE(a, 2) OVER (ORDER BY a) FROM nth_example;

+------+-----------------------------------+
| a    | NTH_VALUE(a, 2) OVER (ORDER BY a) |
+------+-----------------------------------+
|    1 |                              NULL |
|    2 |                                 2 |
|    3 |                                 2 |
|    4 |                                 2 |
+------+-----------------------------------+

SQL

SELECT a, NTH_VALUE(a, case when a > 2 then 1 else 2 end) OVER
        (ORDER BY a rows between unbounded preceding and unbounded following) as nth_value FROM nth_example;

+------+-----------+
| a    | nth_value |
+------+-----------+
|    1 |         2 |
|    2 |         2 |
|    3 |         1 |
|    4 |         1 |
+------+-----------+