test> db.createCollection("tarr")
db.createCollection("tarr")
{ ok: 1 }
test> db.tarr.insertMany(
[
{
  "id": 1,
  "zip": 11111
},
{
  "id": 2,
  "zip": [12345, 54321]
},
{
  "id": 3,
  "zip": [99999, 11111]
},
{
  "id": 3,
  "zip": ["99999", "11111"]
}
]
)
db.tarr.insertMany(
... [
... {
...   "id": 1,
...   "zip": 11111
... },
... {
...   "id": 2,
...   "zip": [12345, 54321]
... },
... {
...   "id": 3,
...   "zip": [99999, 11111]
... },
... {
...   "id": 3,
...   "zip": ["99999", "11111"]
... }
... ]
... )
{
  acknowledged: true,
  insertedIds: {
    '0': ObjectId('68a409b81f487b865189b044'),
    '1': ObjectId('68a409b81f487b865189b045'),
    '2': ObjectId('68a409b81f487b865189b046'),
    '3': ObjectId('68a409b81f487b865189b047')
  }
}
test> test> test> test> db.tarr.find({"zip": 11111})
db.tarr.find({"zip": 11111})
[
  { _id: ObjectId('68a409b81f487b865189b044'), id: 1, zip: 11111 },
  {
    _id: ObjectId('68a409b81f487b865189b046'),
    id: 3,
    zip: [ 99999, 11111 ]
  }
]
test> db.tarr.find({"zip": {$gt: 20000}})
db.tarr.find({"zip": {$gt: 20000}})
[
  {
    _id: ObjectId('68a409b81f487b865189b045'),
    id: 2,
    zip: [ 12345, 54321 ]
  },
  {
    _id: ObjectId('68a409b81f487b865189b046'),
    id: 3,
    zip: [ 99999, 11111 ]
  }
]
test> db.tarr.find({"zip": {$lt: 20000}})
db.tarr.find({"zip": {$lt: 20000}})
[
  { _id: ObjectId('68a409b81f487b865189b044'), id: 1, zip: 11111 },
  {
    _id: ObjectId('68a409b81f487b865189b045'),
    id: 2,
    zip: [ 12345, 54321 ]
  },
  {
    _id: ObjectId('68a409b81f487b865189b046'),
    id: 3,
    zip: [ 99999, 11111 ]
  }
]

mysql> create table t1 (c json);
Query OK, 0 rows affected (0.136 sec)

mysql> insert into t1 values ('{"id": 1, "zip": 11111}');
Query OK, 1 row affected (0.024 sec)

mysql> insert into t1 values ('{"id": 2, "zip": [12345, 54321]}');
Query OK, 1 row affected (0.029 sec)

mysql> insert into t1 values ('{"id": 3, "zip": [99999, 11111]}');
Query OK, 1 row affected (0.031 sec)

mysql> insert into t1 values ('{"id": 3, "zip": ["99999", "11111"]}');
Query OK, 1 row affected (0.028 sec)

mysql> CREATE INDEX zips ON t1 ( (CAST(c->'$.zip' AS UNSIGNED ARRAY)) );
Query OK, 0 rows affected (0.191 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from t1 where 11111 member of(c->'$.zip');
+--------------------------------------+
| c                                    |
+--------------------------------------+
| {"id": 1, "zip": 11111}              |
| {"id": 3, "zip": [99999, 11111]}     |
| {"id": 3, "zip": ["99999", "11111"]} |
+--------------------------------------+
3 rows in set (0.014 sec)

mysql> select * from t1 where "11111" member of(c->'$.zip');
+--------------------------------------+
| c                                    |
+--------------------------------------+
| {"id": 3, "zip": ["99999", "11111"]} |
+--------------------------------------+
1 row in set (0.004 sec)

mysql> select * from t1 where 22222 > (c->'$.zip');
+-------------------------+
| c                       |
+-------------------------+
| {"id": 1, "zip": 11111} |
+-------------------------+
1 row in set (0.003 sec)

mysql> select * from t1 where 11111 = (c->'$.zip');
+-------------------------+
| c                       |
+-------------------------+
| {"id": 1, "zip": 11111} |
+-------------------------+
1 row in set (0.004 sec)

mysql> insert into t1 values ('{"id": 4, "zip": [12345, 54321], "zip2": [12345, 54321]}');
Query OK, 1 row affected (0.024 sec)

mysql> CREATE INDEX zips2 ON t1 ( (CAST(c->'$.zip' AS UNSIGNED ARRAY)), (CAST(c->'$.zip2' AS UNSIGNED ARRAY)) );
ERROR 1235 (42000): This version of MySQL doesn't yet support 'more than one multi-valued key part per index'