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

The date histogram aggregation constructs a histogram for date fields.

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

```python Django
from paradedb import Agg, All, ParadeDB

MockItem.objects.filter(
    id=ParadeDB(All())
).aggregate(agg=Agg('{"date_histogram": {"field": "created_at", "fixed_interval": "30d"}}'))
```

```python SQLAlchemy
from sqlalchemy import select
from sqlalchemy.orm import Session
from paradedb.sqlalchemy import facets, pdb, search

stmt = (
    select(pdb.agg(facets.date_histogram(field="created_at", fixed_interval="30d")))
    .select_from(MockItem)
    .where(search.all(MockItem.id))
)

with Session(engine) as session:
    session.execute(stmt).all()
```

```ruby Rails
MockItem.search(:id)
        .match_all
        .facets_agg(agg: ParadeDB::Aggregations.date_histogram(:created_at, fixed_interval: "30d"))
```

</CodeGroup>

```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.
