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('{"alpha": 1, "beta": 2}'); **** +----------------------------------------+ | JSON_LENGTH('{"alpha": 1, "beta": 2}') | +----------------------------------------+ | 2 | +----------------------------------------+
Note
A JSON or Javascript null value is distinct from SQL NULL.