# $dateHistogram

`$dateHistogram` groups date values into fixed time buckets.

Use it for time-series analytics like events per hour/day.

### Compatibility

| Field Type | Supported |
|------------|-----------|
| TEXT | No |
| U64/I64/F64 | No |
| DATE | Yes |
| BOOL | No |
| KEYWORD | No |
| FACET | No |

Field must be `FAST`.

### Arguments

| Argument | Type | Required | Description |
|----------|------|----------|-------------|
| `field` | `string` | Yes | Date field to bucket on. |
| `fixedInterval` | `string` | Yes | Interval string such as `"1m"`, `"1h"`, `"1d"`. |
| `offset` | `string` | No | Shift bucket boundaries. |
| `minDocCount` | `number` | No | Exclude buckets with fewer docs. |
| `hardBounds` | `{ min: number, max: number }` | No | Hard clamp for bucket range. |
| `extendedBounds` | `{ min: number, max: number }` | No | Emit buckets across this range, including empty ones. |
| `keyed` | `boolean` | No | If `true`, returns buckets as an object. Default: `false`. |

For `hardBounds` and `extendedBounds`, both `min` and `max` are required.

<Tabs>

<Tab title="TypeScript">
```ts
await index.aggregate({
  aggregations: {
    by_day: {
      $dateHistogram: {
        field: "createdAt",
        fixedInterval: "1d",
      },
    },
  },
});
```
</Tab>

<Tab title="Python">
```python
index.aggregate(
    aggregations={
        "by_day": {
            "$dateHistogram": {
                "field": "createdAt",
                "fixedInterval": "1d",
            }
        }
    }
)
```
</Tab>

<Tab title="Redis CLI">
```bash
SEARCH.AGGREGATE logs '{}' '{"by_day": {"$dateHistogram": {"field": "createdAt", "fixedInterval": "1d"}}}'
```
</Tab>

</Tabs>

### Output

```json
{
  "by_day": {
    "buckets": [
      { "key": 1704067200000, "keyAsString": "2024-01-01T00:00:00Z", "docCount": 14 },
      { "key": 1704153600000, "keyAsString": "2024-01-02T00:00:00Z", "docCount": 9 }
    ]
  }
}
```