# COLLECT\_UNIQUE

```
COLLECT_UNIQUE(expr, maxN)
```

Returns an array of unique values in which each value in the input set is assigned to an element of the array.

Available in:

| Processor (stateless) | Processors (stateful) | SQL Studio |
| --------------------- | --------------------- | ---------- |
| ✓                     |                       | ✓          |

*Sample code:*

```sql
USE `kafka`;
SELECT COLLECT_UNIQUE(total, 5) 
FROM orders-events
```

*Output:*

```json
{
  "value": {
    "COLLECT_UNIQUE": [
      56.8,
      25.75,
      88.97,
      19.47,
      99.26
    ]
  }
}
```