Description of json_object
JSON_OBJECT ( [ [ KEY ] key_expr VALUE val_expr [ FORMAT JSON ] ,]... [ JSON_on_null_clause ] [ JSON_returning_clause ] [ STRICT ] [ WITH UNIQUE KEYS ] )
JSON_OBJECT ( [ [ KEY ] key_expr VALUE val_expr [ FORMAT JSON ] ,]... [ JSON_on_null_clause ] [ JSON_returning_clause ] [ STRICT ] [ WITH UNIQUE KEYS ] )