# COALESCE

```
COALESCE(value, prevValue)
```

Returns the first non-null expression in the expression list.

Available in:

| Processors | SQL Studio |
| ---------- | ---------- |
| ✓          | ✓          |

*Sample code:*

```sql
USE `kafka`;
SELECT 
    COALESCE(modified_at, "not updated") AS modified_at 
FROM users-events
WHERE modified_at IS NULL
LIMIT 1;
```

Output:

```json
{
  "value": {
    "modified_at": "not updated"
  }
}
```

In case you want to know more about nullability scenarios, see [`here`](https://docs.lenses.io/latest/devx/6.0/user-guide/applications/sql-processors/nullibility).