WARNING: Version 5.x has passed its EOL date.

This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.

« Children Aggregation Usage Handling responses »

› › ›

Date Histogram Aggregation Usage

edit

Date Histogram Aggregation Usage

edit

A multi-bucket aggregation similar to the histogram except it can only be applied on date values. From a functionality perspective, this histogram supports the same features as the normal histogram. The main difference is that the interval can be specified by date/time expressions.

When specifying a format and extended_bounds or missing, in order for Elasticsearch to be able to parse the serialized DateTime of extended_bounds or missing correctly, the date_optional_time format is included as part of the format value.

Be sure to read the Elasticsearch documentation on Date Histogram Aggregation.

Fluent DSL example

edit

s => s
.Size(0)
.Aggregations(aggs => aggs
    .DateHistogram("projects_started_per_month", date => date
        .Field(p => p.StartedOn)
        .Interval(DateInterval.Month)
        .MinimumDocumentCount(2)
        .Format("yyyy-MM-dd'T'HH:mm:ss")
        .ExtendedBoundsDateMath(FixedDate.AddYears(-1), FixedDate.AddYears(1))
        .Order(HistogramOrder.CountAscending)
        .Missing(FixedDate)
        .Aggregations(childAggs => childAggs
            .Nested("project_tags", n => n
                .Path(p => p.Tags)
                .Aggregations(nestedAggs => nestedAggs
                    .Terms("tags", avg => avg.Field(p => p.Tags.First().Name))
                )
            )
        )
    )
)

Object Initializer syntax example

edit

new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new DateHistogramAggregation("projects_started_per_month")
    {
        Field = Field<Project>(p => p.StartedOn),
        Interval = DateInterval.Month,
        MinimumDocumentCount = 2,
        Format = "yyyy-MM-dd'T'HH:mm:ss",
        ExtendedBoundsDateMath = new ExtendedBounds<DateMath>
        {
            Minimum = FixedDate.AddYears(-1),
            Maximum = FixedDate.AddYears(1),
        },
        Order = HistogramOrder.CountAscending,
        Missing = FixedDate,
        Aggregations = new NestedAggregation("project_tags")
        {
            Path = Field<Project>(p => p.Tags),
            Aggregations = new TermsAggregation("tags")
            {
                Field = Field<Project>(p => p.Tags.First().Name)
            }
        }
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "projects_started_per_month": {
      "date_histogram": {
        "field": "startedOn",
        "interval": "month",
        "min_doc_count": 2,
        "format": "yyyy-MM-dd'T'HH:mm:ss||date_optional_time",
        "order": {
          "_count": "asc"
        },
        "extended_bounds": {
          "min": "2014-06-06T12:01:02.123",
          "max": "2016-06-06T12:01:02.123"
        },
        "missing": "2015-06-06T12:01:02.123"
      },
      "aggs": {
        "project_tags": {
          "nested": {
            "path": "tags"
          },
          "aggs": {
            "tags": {
              "terms": {
                "field": "tags.name"
              }
            }
          }
        }
      }
    }
  }
}

« Children Aggregation Usage Handling responses »