---
title: Date Histogram
description: Count the number of occurrences over fixed time intervals
canonical: https://docs.paradedb.com/documentation/aggregates/datehistogram
---

The date histogram aggregation constructs a histogram for date fields.

```sql
SELECT pdb.agg('{"date_histogram": {"field": "created_at", "fixed_interval": "30d"}}')
FROM mock_items
WHERE id @@@ pdb.all();
```

```ini Expected Response

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 {"buckets": [{"key": 1679616000000.0, "doc_count": 14, "key_as_string": "2023-03-24T00:00:00Z"}, {"key": 1682208000000.0, "doc_count": 27, "key_as_string": "2023-04-23T00:00:00Z"}]}
(1 row)
```

See the [Tantivy documentation](https://docs.rs/tantivy/latest/tantivy/aggregation/bucket/struct.DateHistogramAggregationReq.html)
for all available options.
