FLATTEN(...)
All functions > ARRAY > FLATTEN(...)
Flattens a nested array structure into a single-level array.
Syntax
FLATTEN(array, array, ...)
Notes
- Flattens one level of nesting
- Preserves element order
- Works with any array element type
- Empty nested arrays are removed from result
See also
Examples
FeatureQL
SELECT
-- Flatten numeric arrays
f1 := FLATTEN(ARRAY(1, 2, 3), ARRAY(4, 5, 6)),
-- Flatten string arrays
f2 := FLATTEN(ARRAY('A', 'B'), ARRAY('C'), ARRAY('D', 'E')),
-- Empty arrays ignored
f3 := FLATTEN(ARRAY()::BIGINT[], ARRAY(1, 2), ARRAY()::BIGINT[])
;Result
| f1 ARRAY | f2 ARRAY | f3 ARRAY |
|---|---|---|
| [1, 2, 3, 4, 5, 6] | [A, B, C, D, E] | [1, 2] |