Syntax:
JSON_CONTAINS_PATH(json_doc, one_or_all, path[, path] ...)

Returns 0 or 1 to indicate whether a JSON document contains data at a
given path or paths. Returns NULL if any argument is NULL. An error
occurs if the json_doc argument is not a valid JSON document, any path
argument is not a valid path expression, or one_or_all is not 'one' or
'all'.

To check for a specific value at a path, use JSON_CONTAINS() instead.

The return value is 0 if no specified path exists within the document.
Otherwise, the return value depends on the one_or_all argument:

o 'one': 1 if at least one path exists within the document, 0
  otherwise.

o 'all': 1 if all paths exist within the document, 0 otherwise.

URL: http://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html

