leadInFrame
Returns a value evaluated at the row that is offset rows after the current row within the ordered frame.
Danger
leadInFrame
behavior differs from the standard SQL lead
window function.
Clickhouse window function leadInFrame
respects the window frame.
To get behavior identical to the lead
, use ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
.
Syntax
For more detail on window function syntax see: Window Functions - Syntax.
Parameters
x
— Column name.offset
— Offset to apply. (U)Int*. (Optional -1
by default).default
— Value to return if calculated row exceeds the boundaries of the window frame. (Optional - default value of column type when omitted).
Returned value
- value evaluated at the row that is offset rows after the current row within the ordered frame.
Example
This example looks at historical data for Nobel Prize winners and uses the leadInFrame
function to return a list of successive winners in the physics category.
Query:
Result: