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<p>In Apache Druid (incubating), the topN metric spec specifies how topN values should be sorted.</p>
<h2><a class="anchor" aria-hidden="true" id="numeric-topnmetricspec"></a><a href="#numeric-topnmetricspec" 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>Numeric TopNMetricSpec</h2>
<p>The simplest metric specification is a String value indicating the metric to sort topN results by. They are included in a topN query with:</p>
<pre><code class="hljs css language-json">"metric": "&lt;metric_name&gt;"
</code></pre>
<p>The metric field can also be given as a JSON object. The grammar for dimension values sorted by numeric value is shown below:</p>
<pre><code class="hljs css language-json">"metric": {
    "type": "numeric",
    "metric": "&lt;metric_name&gt;"
}
</code></pre>
<table>
<thead>
<tr><th>property</th><th>description</th><th>required?</th></tr>
</thead>
<tbody>
<tr><td>type</td><td>this indicates a numeric sort</td><td>yes</td></tr>
<tr><td>metric</td><td>the actual metric field in which results will be sorted by</td><td>yes</td></tr>
</tbody>
</table>
<h2><a class="anchor" aria-hidden="true" id="dimension-topnmetricspec"></a><a href="#dimension-topnmetricspec" 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>Dimension TopNMetricSpec</h2>
<p>This metric specification sorts TopN results by dimension value, using one of the sorting orders described here: <a href="/docs/latest/querying/sorting-orders.html">Sorting Orders</a></p>
<table>
<thead>
<tr><th>property</th><th>type</th><th>description</th><th>required?</th></tr>
</thead>
<tbody>
<tr><td>type</td><td>String</td><td>this indicates a sort a dimension's values</td><td>yes, must be 'dimension'</td></tr>
<tr><td>ordering</td><td>String</td><td>Specifies the sorting order. Can be one of the following values: &quot;lexicographic&quot;, &quot;alphanumeric&quot;, &quot;numeric&quot;, &quot;strlen&quot;. See <a href="/docs/latest/querying/sorting-orders.html">Sorting Orders</a> for more details.</td><td>no, default: &quot;lexicographic&quot;</td></tr>
<tr><td>previousStop</td><td>String</td><td>the starting point of the sort. For example, if a previousStop value is 'b', all values before 'b' are discarded. This field can be used to paginate through all the dimension values.</td><td>no</td></tr>
</tbody>
</table>
<p>The following metricSpec uses lexicographic sorting.</p>
<pre><code class="hljs css language-json">"metric": {
    "type": "dimension",
    "ordering": "lexicographic",
    "previousStop": "&lt;previousStop_value&gt;"
}
</code></pre>
<p>Note that in earlier versions of Druid, the functionality provided by the DimensionTopNMetricSpec was handled by two separate spec types, Lexicographic and Alphanumeric (when only two sorting orders were supported). These spec types have been deprecated but are still usable.</p>
<h2><a class="anchor" aria-hidden="true" id="inverted-topnmetricspec"></a><a href="#inverted-topnmetricspec" 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>Inverted TopNMetricSpec</h2>
<p>Sort dimension values in inverted order, i.e inverts the order of the delegate metric spec. It can be used to sort the values in ascending order.</p>
<pre><code class="hljs css language-json">"metric": {
    "type": "inverted",
    "metric": &lt;delegate_top_n_metric_spec&gt;
}
</code></pre>
<table>
<thead>
<tr><th>property</th><th>description</th><th>required?</th></tr>
</thead>
<tbody>
<tr><td>type</td><td>this indicates an inverted sort</td><td>yes</td></tr>
<tr><td>metric</td><td>the delegate metric spec.</td><td>yes</td></tr>
</tbody>
</table>
</span></div></article></div><div class="docs-prevnext"><a class="docs-prev button" href="/docs/latest/querying/sorting-orders.html"><span class="arrow-prev">← </span><span>Sorting Orders</span></a><a class="docs-next button" href="/docs/latest/querying/virtual-columns.html"><span>Virtual Columns</span><span class="arrow-next"> →</span></a></div></div></div><nav class="onPageNav"><ul class="toc-headings"><li><a href="#numeric-topnmetricspec">Numeric TopNMetricSpec</a></li><li><a href="#dimension-topnmetricspec">Dimension TopNMetricSpec</a></li><li><a href="#inverted-topnmetricspec">Inverted TopNMetricSpec</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/incubator-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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