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Version: Latest-3.5

array_flatten

array_flatten flattens one layer of nested arrays.

Syntax​

array_flatten(param)

Parameters​

param: a nested array that needs to be flattened. Only nested arrays are supported, and it can be a multi-level nested array, the elements of the array can be any data type supported by StarRocks.

Return value​

The data type of the return value is an array type after flattening one layer.

Examples​

Example 1: Flatten a 2-level nested array.

mysql> SELECT array_flatten([[1, 2], [1, 4]]) as res;
+-----------+
| res       |
+-----------+
| [1,2,1,4] |
+-----------+

Example 2: Flatten a 3-level nested array.

mysql> SELECT array_flatten([[[1],[2]], [[3],[4]]]) as res;
+-------------------+
| res               |
+-------------------+
| [[1],[2],[3],[4]] |
+-------------------+