Extracting a JSON value

com-id.sql

SELECT 
  properties,
  JSON_EXTRACT_SCALAR(properties, "$.com_id") AS com_id
FROM mp.event
WHERE name = "Signed Up"
LIMIT 1

+-----------------+--------+
|   properties    | com_id |
+-----------------+--------+
| {"com_id":1234} |   1234 |
+-----------------+--------+