Recently I wanted to filter out records that contain a certain keyword array in MongoDB, for example: I have five records that contain keywords array:

```
{a:[1,2]}
{a:[1,3,8]}
{a:[1,2,5]}
{a:[3,5,1]}
{a:[4,5]}

```

If I input the array `[1,2,3,5]` for search, then I want to get:

```
{a:[1,2]}
{a:[1,2,5]}
{a:[3,5,1]}

```

Each of them is a sub array of `[1,2,3,5]`.

Any idea?

Please don't use a where clause (when possbile). Thanks!