UNNEST
Written by
Updated at June 27, 2023
Syntax
UNNEST( array )
Description
Expands the array array expression to a set of rows.
Argument types:
array—Array of fractional numbers | Array of integers | Array of strings
Return type: Depends on argument types
Note
PostgreSQL doesn't allow filtering fields containing the UNNEST function. If the data source is PostgreSQL, do not use such fields in selectors.
Example
Source data
| City | Category |
|---|---|
'Moscow' |
['Office Supplies', 'Furniture'] |
'London' |
['Office Supplies'] |
Result
| [City] | UNNEST([Category]) |
|---|---|
'Moscow' |
'Office Supplies' |
'Moscow' |
'Furniture' |
'London' |
'Office Supplies' |
Data source support
ClickHouse 21.8, PostgreSQL 9.3.