JSON_LENGTH
Computes the length of a JSON map or array.
JSON_LENGTH(json)
Arguments
json: a valid JSON array or map.
Return Value
the length as an integer
SQL NULL if json is not a valid JSON array or map
Examples
SELECT JSON_LENGTH('true'); +---------------------+ | JSON_LENGTH('true') | +---------------------+ | NULL | +---------------------+ SELECT JSON_LENGTH('[1,2,3]'); +------------------------+ | JSON_LENGTH('[1,2,3]') | +------------------------+ | 3 | +------------------------+ SELECT JSON_LENGTH('{"a": 1, "b": 2}'); +---------------------------------+ | JSON_LENGTH('{"a": 1, "b": 2}') | +---------------------------------+ | 2 | +---------------------------------+
Notice
A JSON or Javascript null value is distinct from SQL NULL.