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| </script></nav></div><div class="container mainContainer docsContainer"><div class="wrapper"><div class="post"><header class="postHeader"><a class="edit-page-link button" href="https://github.com/apache/druid/edit/master/docs/querying/multi-value-dimensions.md" target="_blank" rel="noreferrer noopener">Edit</a><h1 id="__docusaurus" class="postHeaderTitle">Multi-value dimensions</h1></header><article><div><span><!-- |
| ~ Licensed to the Apache Software Foundation (ASF) under one |
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| <p>Apache Druid supports "multi-value" string dimensions. Multi-value string dimensions result from input fields that contain an |
| array of values instead of a single value, such as the <code>tags</code> values in the following JSON array example:</p> |
| <pre><code class="hljs">{<span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"2011-01-12T00:00:00.000Z"</span>, <span class="hljs-attr">"tags"</span>: [<span class="hljs-string">"t1"</span>,<span class="hljs-string">"t2"</span>,<span class="hljs-string">"t3"</span>]} |
| </code></pre> |
| <p>This document describes filtering and grouping behavior for multi-value dimensions. For information about the internal representation of multi-value dimensions, see |
| <a href="/docs/latest/design/segments.html#multi-value-columns">segments documentation</a>. Examples in this document |
| are in the form of <a href="/docs/latest/querying/querying.html">native Druid queries</a>. Refer to the <a href="/docs/latest/querying/sql-multivalue-string-functions.html">Druid SQL documentation</a> for details |
| about using multi-value string dimensions in SQL.</p> |
| <h2><a class="anchor" aria-hidden="true" id="overview"></a><a href="#overview" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Overview</h2> |
| <p>At ingestion time, Druid can detect multi-value dimensions and configure the <code>dimensionsSpec</code> accordingly. It detects JSON arrays or CSV/TSV fields as multi-value dimensions.</p> |
| <p>For TSV or CSV data, you can specify the multi-value delimiters using the <code>listDelimiter</code> field in the <code>parseSpec</code>. JSON data must be formatted as a JSON array to be ingested as a multi-value dimension. JSON data does not require <code>parseSpec</code> configuration.</p> |
| <p>The following shows an example multi-value dimension named <code>tags</code> in a <code>dimensionsSpec</code>:</p> |
| <pre><code class="hljs"><span class="hljs-string">"dimensions"</span>: [ |
| { |
| <span class="hljs-string">"type"</span>: <span class="hljs-string">"string"</span>, |
| <span class="hljs-string">"name"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-string">"multiValueHandling"</span>: <span class="hljs-string">"SORTED_ARRAY"</span>, |
| <span class="hljs-string">"createBitmapIndex"</span>: <span class="hljs-literal">true</span> |
| } |
| ], |
| </code></pre> |
| <p>By default, Druid sorts values in multi-value dimensions. This behavior is controlled by the <code>SORTED_ARRAY</code> value of the <code>multiValueHandling</code> field. Alternatively, you can specify multi-value handling as:</p> |
| <ul> |
| <li><code>SORTED_SET</code>: results in the removal of duplicate values</li> |
| <li><code>ARRAY</code>: retains the original order of the values</li> |
| </ul> |
| <p>See <a href="/docs/latest/ingestion/ingestion-spec.html#dimension-objects">Dimension Objects</a> for information on configuring multi-value handling.</p> |
| <h2><a class="anchor" aria-hidden="true" id="querying-multi-value-dimensions"></a><a href="#querying-multi-value-dimensions" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Querying multi-value dimensions</h2> |
| <p>The following sections describe filtering and grouping behavior based on the following example data, which includes a multi-value dimension, <code>tags</code>.</p> |
| <pre><code class="hljs">{<span class="hljs-string">"timestamp"</span>: <span class="hljs-string">"2011-01-12T00:00:00.000Z"</span>, <span class="hljs-string">"tags"</span>: [<span class="hljs-string">"t1"</span>,<span class="hljs-string">"t2"</span>,<span class="hljs-string">"t3"</span>]} <span class="hljs-meta">#row1</span> |
| {<span class="hljs-string">"timestamp"</span>: <span class="hljs-string">"2011-01-13T00:00:00.000Z"</span>, <span class="hljs-string">"tags"</span>: [<span class="hljs-string">"t3"</span>,<span class="hljs-string">"t4"</span>,<span class="hljs-string">"t5"</span>]} <span class="hljs-meta">#row2</span> |
| {<span class="hljs-string">"timestamp"</span>: <span class="hljs-string">"2011-01-14T00:00:00.000Z"</span>, <span class="hljs-string">"tags"</span>: [<span class="hljs-string">"t5"</span>,<span class="hljs-string">"t6"</span>,<span class="hljs-string">"t7"</span>]} <span class="hljs-meta">#row3</span> |
| {<span class="hljs-string">"timestamp"</span>: <span class="hljs-string">"2011-01-14T00:00:00.000Z"</span>, <span class="hljs-string">"tags"</span>: []} <span class="hljs-meta">#row4</span> |
| </code></pre> |
| <blockquote> |
| <p>Be sure to remove the comments before trying out the sample data.</p> |
| </blockquote> |
| <h3><a class="anchor" aria-hidden="true" id="filtering"></a><a href="#filtering" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Filtering</h3> |
| <p>All query types, as well as <a href="/docs/latest/querying/aggregations.html#filtered-aggregator">filtered aggregators</a>, can filter on multi-value |
| dimensions. Filters follow these rules on multi-value dimensions:</p> |
| <ul> |
| <li>Value filters (like "selector", "bound", and "in") match a row if any of the values of a multi-value dimension match |
| the filter.</li> |
| <li>The Column Comparison filter will match a row if the dimensions have any overlap.</li> |
| <li>Value filters that match <code>null</code> or <code>""</code> (empty string) will match empty cells in a multi-value dimension.</li> |
| <li>Logical expression filters behave the same way they do on single-value dimensions: "and" matches a row if all |
| underlying filters match that row; "or" matches a row if any underlying filters match that row; "not" matches a row |
| if the underlying filter does not match the row.</li> |
| </ul> |
| <p>The following example illustrates these rules. This query applies an "or" filter to match row1 and row2 of the dataset above, but not row3:</p> |
| <pre><code class="hljs">{ |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"or"</span>, |
| <span class="hljs-attr">"fields"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t1"</span> |
| }, |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t3"</span> |
| } |
| ] |
| } |
| </code></pre> |
| <p>This "and" filter would match only row1 of the dataset above:</p> |
| <pre><code class="hljs">{ |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"and"</span>, |
| <span class="hljs-attr">"fields"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t1"</span> |
| }, |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t3"</span> |
| } |
| ] |
| } |
| </code></pre> |
| <p>This "selector" filter would match row4 of the dataset above:</p> |
| <pre><code class="hljs">{ |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-literal">null</span> |
| } |
| </code></pre> |
| <h3><a class="anchor" aria-hidden="true" id="grouping"></a><a href="#grouping" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Grouping</h3> |
| <p>topN and groupBy queries can group on multi-value dimensions. When grouping on a multi-value dimension, <em>all</em> values |
| from matching rows will be used to generate one group per value. This can be thought of as the equivalent to the |
| <code>UNNEST</code> operator used on an <code>ARRAY</code> type that many SQL dialects support. This means it's possible for a query to return |
| more groups than there are rows. For example, a topN on the dimension <code>tags</code> with filter <code>"t1" AND "t3"</code> would match |
| only row1, and generate a result with three groups: <code>t1</code>, <code>t2</code>, and <code>t3</code>. If you only need to include values that match |
| your filter, you can use a <a href="/docs/latest/querying/dimensionspecs.html#filtered-dimensionspecs">filtered dimensionSpec</a>. This can also |
| improve performance.</p> |
| <h2><a class="anchor" aria-hidden="true" id="example-groupby-query-with-no-filtering"></a><a href="#example-groupby-query-with-no-filtering" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Example: GroupBy query with no filtering</h2> |
| <p>See <a href="/docs/latest/querying/groupbyquery.html">GroupBy querying</a> for details.</p> |
| <pre><code class="hljs css language-json">{ |
| <span class="hljs-attr">"queryType"</span>: <span class="hljs-string">"groupBy"</span>, |
| <span class="hljs-attr">"dataSource"</span>: <span class="hljs-string">"test"</span>, |
| <span class="hljs-attr">"intervals"</span>: [ |
| <span class="hljs-string">"1970-01-01T00:00:00.000Z/3000-01-01T00:00:00.000Z"</span> |
| ], |
| <span class="hljs-attr">"granularity"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"all"</span> |
| }, |
| <span class="hljs-attr">"dimensions"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"default"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"outputName"</span>: <span class="hljs-string">"tags"</span> |
| } |
| ], |
| <span class="hljs-attr">"aggregations"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"count"</span>, |
| <span class="hljs-attr">"name"</span>: <span class="hljs-string">"count"</span> |
| } |
| ] |
| } |
| </code></pre> |
| <p>This query returns the following result:</p> |
| <pre><code class="hljs css language-json">[ |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t1"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t2"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">2</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t3"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t4"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">2</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t5"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t6"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t7"</span> |
| } |
| } |
| ] |
| </code></pre> |
| <p>Notice that original rows are "exploded" into multiple rows and merged.</p> |
| <h2><a class="anchor" aria-hidden="true" id="example-groupby-query-with-a-selector-query-filter"></a><a href="#example-groupby-query-with-a-selector-query-filter" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Example: GroupBy query with a selector query filter</h2> |
| <p>See <a href="/docs/latest/querying/filters.html">query filters</a> for details of selector query filter.</p> |
| <pre><code class="hljs css language-json">{ |
| <span class="hljs-attr">"queryType"</span>: <span class="hljs-string">"groupBy"</span>, |
| <span class="hljs-attr">"dataSource"</span>: <span class="hljs-string">"test"</span>, |
| <span class="hljs-attr">"intervals"</span>: [ |
| <span class="hljs-string">"1970-01-01T00:00:00.000Z/3000-01-01T00:00:00.000Z"</span> |
| ], |
| <span class="hljs-attr">"filter"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t3"</span> |
| }, |
| <span class="hljs-attr">"granularity"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"all"</span> |
| }, |
| <span class="hljs-attr">"dimensions"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"default"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"outputName"</span>: <span class="hljs-string">"tags"</span> |
| } |
| ], |
| <span class="hljs-attr">"aggregations"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"count"</span>, |
| <span class="hljs-attr">"name"</span>: <span class="hljs-string">"count"</span> |
| } |
| ] |
| } |
| </code></pre> |
| <p>This query returns the following result:</p> |
| <pre><code class="hljs css language-json">[ |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t1"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t2"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">2</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t3"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t4"</span> |
| } |
| }, |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">1</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t5"</span> |
| } |
| } |
| ] |
| </code></pre> |
| <p>You might be surprised to see "t1", "t2", "t4" and "t5" included in the results. This is because the query filter is |
| applied on the row before explosion. For multi-value dimensions, a selector filter for "t3" would match row1 and row2, |
| after which exploding is done. For multi-value dimensions, a query filter matches a row if any individual value inside |
| the multiple values matches the query filter.</p> |
| <h2><a class="anchor" aria-hidden="true" id="example-groupby-query-with-selector-query-and-dimension-filters"></a><a href="#example-groupby-query-with-selector-query-and-dimension-filters" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Example: GroupBy query with selector query and dimension filters</h2> |
| <p>To solve the problem above and to get only rows for "t3", use a "filtered dimension spec", as in the query below.</p> |
| <p>See filtered <code>dimensionSpecs</code> in <a href="/docs/latest/querying/dimensionspecs.html#filtered-dimensionspecs">dimensionSpecs</a> for details.</p> |
| <pre><code class="hljs css language-json">{ |
| <span class="hljs-attr">"queryType"</span>: <span class="hljs-string">"groupBy"</span>, |
| <span class="hljs-attr">"dataSource"</span>: <span class="hljs-string">"test"</span>, |
| <span class="hljs-attr">"intervals"</span>: [ |
| <span class="hljs-string">"1970-01-01T00:00:00.000Z/3000-01-01T00:00:00.000Z"</span> |
| ], |
| <span class="hljs-attr">"filter"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"selector"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"value"</span>: <span class="hljs-string">"t3"</span> |
| }, |
| <span class="hljs-attr">"granularity"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"all"</span> |
| }, |
| <span class="hljs-attr">"dimensions"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"listFiltered"</span>, |
| <span class="hljs-attr">"delegate"</span>: { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"default"</span>, |
| <span class="hljs-attr">"dimension"</span>: <span class="hljs-string">"tags"</span>, |
| <span class="hljs-attr">"outputName"</span>: <span class="hljs-string">"tags"</span> |
| }, |
| <span class="hljs-attr">"values"</span>: [<span class="hljs-string">"t3"</span>] |
| } |
| ], |
| <span class="hljs-attr">"aggregations"</span>: [ |
| { |
| <span class="hljs-attr">"type"</span>: <span class="hljs-string">"count"</span>, |
| <span class="hljs-attr">"name"</span>: <span class="hljs-string">"count"</span> |
| } |
| ] |
| } |
| </code></pre> |
| <p>This query returns the following result:</p> |
| <pre><code class="hljs css language-json">[ |
| { |
| <span class="hljs-attr">"timestamp"</span>: <span class="hljs-string">"1970-01-01T00:00:00.000Z"</span>, |
| <span class="hljs-attr">"event"</span>: { |
| <span class="hljs-attr">"count"</span>: <span class="hljs-number">2</span>, |
| <span class="hljs-attr">"tags"</span>: <span class="hljs-string">"t3"</span> |
| } |
| } |
| ] |
| </code></pre> |
| <p>Note that, for groupBy queries, you could get similar result with a <a href="/docs/latest/querying/having.html">having spec</a> but using a filtered |
| <code>dimensionSpec</code> is much more efficient because that gets applied at the lowest level in the query processing pipeline. |
| Having specs are applied at the outermost level of groupBy query processing.</p> |
| <h2><a class="anchor" aria-hidden="true" id="disable-groupby-on-multi-value-columns"></a><a href="#disable-groupby-on-multi-value-columns" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Disable GroupBy on multi-value columns</h2> |
| <p>You can disable the implicit unnesting behavior for groupBy by setting groupByEnableMultiValueUnnesting: false in your |
| query context. In this mode, the groupBy engine will return an error instead of completing the query. This is a safety |
| feature for situations where you believe that all dimensions are singly-valued and want the engine to reject any |
| multi-valued dimensions that were inadvertently included.</p> |
| </span></div></article></div><div class="docs-prevnext"><a class="docs-prev button" href="/docs/latest/querying/lookups.html"><span class="arrow-prev">← </span><span>Lookups</span></a><a class="docs-next button" href="/docs/latest/querying/multitenancy.html"><span>Multitenancy</span><span class="arrow-next"> →</span></a></div></div></div><nav class="onPageNav"><ul class="toc-headings"><li><a href="#overview">Overview</a></li><li><a href="#querying-multi-value-dimensions">Querying multi-value dimensions</a><ul class="toc-headings"><li><a href="#filtering">Filtering</a></li><li><a href="#grouping">Grouping</a></li></ul></li><li><a href="#example-groupby-query-with-no-filtering">Example: GroupBy query with no filtering</a></li><li><a href="#example-groupby-query-with-a-selector-query-filter">Example: GroupBy query with a selector query filter</a></li><li><a href="#example-groupby-query-with-selector-query-and-dimension-filters">Example: GroupBy query with selector query and dimension filters</a></li><li><a href="#disable-groupby-on-multi-value-columns">Disable GroupBy on multi-value columns</a></li></ul></nav></div><footer class="nav-footer druid-footer" id="footer"><div class="container"><div class="text-center"><p><a href="/technology">Technology</a> · <a href="/use-cases">Use Cases</a> · <a href="/druid-powered">Powered by Druid</a> · <a href="/docs/latest/latest">Docs</a> · <a href="/community/">Community</a> · <a href="/downloads.html">Download</a> · <a href="/faq">FAQ</a></p></div><div class="text-center"><a title="Join the user group" href="https://groups.google.com/forum/#!forum/druid-user" target="_blank"><span class="fa fa-comments"></span></a> · <a title="Follow Druid" href="https://twitter.com/druidio" target="_blank"><span class="fab fa-twitter"></span></a> · <a title="Download via Apache" href="https://www.apache.org/dyn/closer.cgi?path=/incubator/druid/{{ site.druid_versions[0].versions[0].version }}/apache-druid-{{ site.druid_versions[0].versions[0].version }}-bin.tar.gz" target="_blank"><span class="fas fa-feather"></span></a> · <a title="GitHub" href="https://github.com/apache/druid" target="_blank"><span class="fab fa-github"></span></a></div><div class="text-center license">Copyright © 2019 <a href="https://www.apache.org/" target="_blank">Apache Software Foundation</a>.<br/>Except where otherwise noted, licensed under <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a>.<br/>Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries.</div></div></footer></div><script type="text/javascript" src="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.js"></script><script> |
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