mirror of https://github.com/apache/druid.git
94 lines
2.3 KiB
Markdown
94 lines
2.3 KiB
Markdown
---
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layout: default
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---
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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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#### 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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<code>"having": {
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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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</code>
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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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<code>"having": {
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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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</code>
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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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<code>"having": {
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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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</code>
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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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<code>"having": {
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"type": "and",
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"havingSpecs": [<having clause>, <having clause>, ...]
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}
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</code>
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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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<code>"having": {
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"type": "or",
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"havingSpecs": [<having clause>, <having clause>, ...]
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}
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</code>
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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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<code>"having": {
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"type": "not",
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"havingSpec": <having clause>
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}
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</code>
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The having clause specified at `havingSpec` can be any other having clause defined on this page.
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