ST_UNION_AGG

Aggregates multiple GEOMETRY values by repeatedly applying ST_UNION and returns the merged GEOMETRY result.

This function supports GEOMETRY only.

Syntax

ST_UNION_AGG(<geometry>)

Arguments

Arguments	Description
<geometry>	An expression of type GEOMETRY.

Return Type

GEOMETRY.

note

• NULL input rows are ignored.
• If all input rows are NULL, the result is NULL.
• If the input GEOMETRY values use different SRIDs, the function returns an error.

Example

WITH data AS (
    SELECT TO_GEOMETRY('POINT(0 0)') AS g
    UNION ALL
    SELECT TO_GEOMETRY('POINT(1 1)')
)
SELECT ST_ASWKT(ST_UNION_AGG(g)) FROM data;

╭───────────────────────────╮
│ st_aswkt(st_union_agg(g)) │
├───────────────────────────┤
│ MULTIPOINT(0 0,1 1)       │
╰───────────────────────────╯