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NTH_
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The NTH_ function returns an expression evaluated at the nth row of the window frame.
If there are fewer than n rows in the frame, returns NULL.
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
CREATE TABLE nth_example (a int, b int);INSERT INTO nth_example VALUES (1, 2), (2, 2), (3, 3), (4, 3);
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 |
+------+-----------------------------------+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 |
+------+-----------+Last modified: