SELECT kind, json_to_string(j) FROM t_legacy_json_non_object ORDER BY kind;

+--------+--------------------------------------------+
| kind   | json_to_string(t_legacy_json_non_object.j) |
+--------+--------------------------------------------+
| array  | [1,2,3]                                    |
| bool   | true                                       |
| int    | 42                                         |
| null   | null                                       |
| object | {"a":10,"msg":"object"}                    |
| string | "hello"                                    |
+--------+--------------------------------------------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_array(j) ORDER BY kind;

+-------+
| kind  |
+-------+
| array |
+-------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_string(j) ORDER BY kind;

+--------+
| kind   |
+--------+
| string |
+--------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_int(j) ORDER BY kind;

+------+
| kind |
+------+
| int  |
+------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_bool(j) ORDER BY kind;

+------+
| kind |
+------+
| bool |
+------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_null(j) ORDER BY kind;

+------+
| kind |
+------+
| null |
+------+

SELECT kind FROM t_legacy_json_non_object WHERE json_is_object(j) ORDER BY kind;

+--------+
| kind   |
+--------+
| object |
+--------+