49 lines
1.4 KiB
Plaintext
49 lines
1.4 KiB
Plaintext
[[search-aggregations-metrics-valuecount-aggregation]]
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=== Value Count
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A `single-value` metrics aggregation that counts the number of values that are extracted from the aggregated documents.
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These values can be extracted either from specific fields in the documents, or be generated by a provided script. Typically,
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this aggregator will be used in conjunction with other single-value aggregations. For example, when computing the `avg`
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one might be interested in the number of values the average is computed over.
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[source,js]
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--------------------------------------------------
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{
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"aggs" : {
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"grades_count" : { "value_count" : { "field" : "grade" } }
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}
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}
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--------------------------------------------------
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Response:
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[source,js]
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--------------------------------------------------
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{
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...
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"aggregations": {
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"grades_count": {
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"value": 10
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}
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}
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}
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--------------------------------------------------
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The name of the aggregation (`grades_count` above) also serves as the key by which the aggregation result can be
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retrieved from the returned response.
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==== Script
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Counting the values generated by a script:
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[source,js]
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--------------------------------------------------
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{
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...,
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"aggs" : {
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"grades_count" : { "value_count" : { "script" : "doc['grade'].value" } }
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}
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}
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-------------------------------------------------- |