2013-09-16 17:49:36 -04:00
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---
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2013-09-26 19:22:28 -04:00
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layout: doc_page
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2013-09-16 17:49:36 -04:00
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---
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2014-01-16 18:37:07 -05:00
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# Filter groupBy Query Results
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2013-09-13 18:20:39 -04:00
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A having clause is a JSON object identifying which rows from a groupBy query should be returned, by specifying conditions on aggregated values.
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It is essentially the equivalent of the HAVING clause in SQL.
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Druid supports the following types of having clauses.
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### Numeric filters
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The simplest having clause is a numeric filter.
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Numeric filters can be used as the base filters for more complex boolean expressions of filters.
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2014-11-03 14:57:52 -05:00
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Here's an example of a having-clause numeric filter:
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```json
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{
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"type": "greaterThan",
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"aggregation": "myAggMetric",
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"value": 100
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}
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2013-09-13 18:20:39 -04:00
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#### Equal To
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The equalTo filter will match rows with a specific aggregate value.
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The grammar for an `equalTo` filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "equalTo",
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"aggregation": "<aggregate_metric>",
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"value": <numeric_value>
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}
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```
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2013-09-13 18:20:39 -04:00
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This is the equivalent of `HAVING <aggregate> = <value>`.
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#### Greater Than
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The greaterThan filter will match rows with aggregate values greater than the given value.
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The grammar for a `greaterThan` filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "greaterThan",
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"aggregation": "<aggregate_metric>",
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"value": <numeric_value>
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}
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```
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2013-09-13 18:20:39 -04:00
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This is the equivalent of `HAVING <aggregate> > <value>`.
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#### Less Than
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The lessThan filter will match rows with aggregate values less than the specified value.
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The grammar for a `greaterThan` filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "lessThan",
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"aggregation": "<aggregate_metric>",
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"value": <numeric_value>
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}
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```
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2013-09-13 18:20:39 -04:00
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This is the equivalent of `HAVING <aggregate> < <value>`.
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### Logical expression filters
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#### AND
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The grammar for an AND filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "and",
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"havingSpecs": [<having clause>, <having clause>, ...]
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}
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```
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2013-09-13 18:20:39 -04:00
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The having clauses in `havingSpecs` can be any other having clause defined on this page.
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#### OR
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The grammar for an OR filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "or",
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"havingSpecs": [<having clause>, <having clause>, ...]
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}
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```
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2013-09-13 18:20:39 -04:00
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The having clauses in `havingSpecs` can be any other having clause defined on this page.
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#### NOT
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The grammar for a NOT filter is as follows:
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2013-09-27 20:08:34 -04:00
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```json
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{
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"type": "not",
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"havingSpec": <having clause>
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}
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```
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2013-09-13 18:20:39 -04:00
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The having clause specified at `havingSpec` can be any other having clause defined on this page.
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