JSON functions can parse a string as the JSON type and extract the fields in JSON. JSON mainly has the following two structures: map and array. If a string fails to be parsed as the JSON type, the returned value is null.

Log Service supports the following common JSON functions.
Function name Meaning Example
json_parse(string) Converts a string to the JSON type. SELECT json_parse('[1, 2, 3]') returns a JSON array
json_format(json) Converts the JSON type to a string. SELECT json_format(json_parse('[1, 2, 3]')) returns a string
json_array_contains(json, value) Determines whether a JSON type value or string (whose content is a JSON array) contains a value or not. SELECT json_array_contains(json_parse('[1, 2, 3]'), 2) or SELECT json_array_contains('[1, 2, 3]', 2)
json_array_get(json_array, index) The same as json_array_contains, which is used to obtain the element of a subscript of a JSON array. SELECT json_array_get('["a", "b", "c"]',  0) returns 'a'
json_array_length(json) Returns the size of the JSON array. SELECT json_array_length('[1, 2, 3]') Returns 3
json_extract(json, json_path) Extracts the value from a JSON object. The JSON path syntax is similar to $.store.book[0].title. The returned result is a JSON object. SELECT json_extract(json, '$.store.book');
json_extract_scalar(json, json_path) Similar to json_extract, but returns a string. -
json_size(json,json_path) Obtains the size of the JSON object or array. Select json_size ('[1, 2, 3]') returns 3