Warning
SingleStore 9.0 gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 8.9 is recommended for production workloads, which can later be upgraded to SingleStore 9.0.
LEAD
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Returns an expression evaluated at some offset after the current row.
If there is no such row returns NULL instead.
Syntax
LEAD ( expression [, offset]) OVER (
[PARTITION BY (col | expr), ...]
[ORDER BY (col | expr), ...]
)Arguments
-
expression: any expression.
This may be a column name, the result of another function, or a math operation -
offset: A constant integer that specifies the number of rows after the current row to evaluate the expression.
Defaults to 1 if not specified
Return Type
The result of expression
Examples
CREATE TABLE lead_example (a int, b int);INSERT INTO lead_example VALUES(1,2),(2,2),(3,3),(4,3);
SELECT a, LEAD(a) OVER(ORDER BY (a)) FROM lead_example;
+------+----------------------------+
| a | LEAD(a) OVER(ORDER BY (a)) |
+------+----------------------------+
| 1 | 2 |
| 2 | 3 |
| 3 | 4 |
| 4 | NULL |
+------+----------------------------+SELECT a, LEAD(a,2) OVER(ORDER BY (a)) FROM lead_example;
+------+------------------------------+
| a | LEAD(a,2) OVER(ORDER BY (a)) |
+------+------------------------------+
| 1 | 3 |
| 2 | 4 |
| 3 | NULL |
| 4 | NULL |
+------+------------------------------+Last modified: February 16, 2023