FLATTEN

Description

The FLATTEN function is used to convert a two-dimensional array (i.e., an array of arrays) into a one-dimensional array. This function can handle complex structures containing multiple sub-arrays and flatten their elements into a continuous sequence.

Syntax

flatten(array<array>)

Parameter Description

• array<array>: A two-dimensional array containing multiple sub-arrays. Each sub-array can contain elements of any type.

Return Value

Returns a one-dimensional array containing all the elements of the sub-arrays.

Usage Example

Example 1: Basic Usage

Suppose we have a two-dimensional array and we want to flatten it into a one-dimensional array.

SELECT FLATTEN(
  ARRAY(
    ARRAY(1, 2),
    ARRAY(3, 4)
  )
);

Return results:

[1, 2, 3, 4]

Example 2: Nested Arrays

If our two-dimensional array contains nested deeper level arrays, the FLATTEN function can also handle it.

SELECT FLATTEN(
  ARRAY(
    ARRAY(ARRAY(1), ARRAY(2, 3)),
    ARRAY(ARRAY(4), ARRAY(5, 6))
  )
);

Return results:

[[1],[2,3],[4],[5,6]]