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<blockquote>
<p>Apache Druid supports two query languages: Druid SQL and <a href="/docs/latest/querying/querying.html">native queries</a>.
This document describes the SQL language.</p>
</blockquote>
<p>Druid supports query context parameters which affect <a href="/docs/latest/querying/sql.html">SQL query</a> planning.
See <a href="/docs/latest/querying/query-context.html">Query context</a> for general query context parameters for all query types.</p>
<h2><a class="anchor" aria-hidden="true" id="sql-query-context-parameters"></a><a href="#sql-query-context-parameters" 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>SQL query context parameters</h2>
<p>Configure Druid SQL query planning using the parameters in the table below.</p>
<table>
<thead>
<tr><th>Parameter</th><th>Description</th><th>Default value</th></tr>
</thead>
<tbody>
<tr><td><code>sqlQueryId</code></td><td>Unique identifier given to this SQL query. For HTTP client, it will be returned in <code>X-Druid-SQL-Query-Id</code> header.<br/><br/>To specify a unique identifier for SQL query, use <code>sqlQueryId</code> instead of <a href="/docs/latest/querying/query-context.html"><code>queryId</code></a>. Setting <code>queryId</code> for a SQL request has no effect. All native queries underlying SQL use an auto-generated <code>queryId</code>.</td><td>auto-generated</td></tr>
<tr><td><code>sqlTimeZone</code></td><td>Sets the time zone for this connection, which will affect how time functions and timestamp literals behave. Should be a time zone name like &quot;America/Los_Angeles&quot; or offset like &quot;-08:00&quot;.</td><td>druid.sql.planner.sqlTimeZone on the Broker (default: UTC)</td></tr>
<tr><td><code>sqlStringifyArrays</code></td><td>When set to true, result columns which return array values will be serialized into a JSON string in the response instead of as an array (default: true, except for JDBC connections, where it is always false)</td></tr>
<tr><td><code>useApproximateCountDistinct</code></td><td>Whether to use an approximate cardinality algorithm for <code>COUNT(DISTINCT foo)</code>.</td><td>druid.sql.planner.useApproximateCountDistinct on the Broker (default: true)</td></tr>
<tr><td><code>useGroupingSetForExactDistinct</code></td><td>Whether to use grouping sets to execute queries with multiple exact distinct aggregations.</td><td>druid.sql.planner.useGroupingSetForExactDistinct on the Broker (default: false)</td></tr>
<tr><td><code>useApproximateTopN</code></td><td>Whether to use approximate <a href="/docs/latest/querying/topnquery.html">TopN queries</a> when a SQL query could be expressed as such. If false, exact <a href="/docs/latest/querying/groupbyquery.html">GroupBy queries</a> will be used instead.</td><td>druid.sql.planner.useApproximateTopN on the Broker (default: true)</td></tr>
</tbody>
</table>
<h2><a class="anchor" aria-hidden="true" id="setting-the-query-context"></a><a href="#setting-the-query-context" 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>Setting the query context</h2>
<p>The query context parameters can be specified as a &quot;context&quot; object in the <a href="/docs/latest/querying/sql-api.html">JSON API</a> or as a <a href="/docs/latest/querying/sql-jdbc.html">JDBC connection properties object</a>.
See examples for each option below.</p>
<h3><a class="anchor" aria-hidden="true" id="example-using-json-api"></a><a href="#example-using-json-api" 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 using JSON API</h3>
<pre><code class="hljs">{
  <span class="hljs-attr">"query"</span> : <span class="hljs-string">"SELECT COUNT(*) FROM data_source WHERE foo = 'bar' AND __time &gt; TIMESTAMP '2000-01-01 00:00:00'"</span>,
  <span class="hljs-attr">"context"</span> : {
    <span class="hljs-attr">"sqlTimeZone"</span> : <span class="hljs-string">"America/Los_Angeles"</span>
  }
}
</code></pre>
<h3><a class="anchor" aria-hidden="true" id="example-using-jdbc"></a><a href="#example-using-jdbc" 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 using JDBC</h3>
<pre><code class="hljs css language-java">String url = <span class="hljs-string">"jdbc:avatica:remote:url=http://localhost:8082/druid/v2/sql/avatica/"</span>;

<span class="hljs-comment">// Set any query context parameters you need here.</span>
Properties connectionProperties = <span class="hljs-keyword">new</span> Properties();
connectionProperties.setProperty(<span class="hljs-string">"sqlTimeZone"</span>, <span class="hljs-string">"America/Los_Angeles"</span>);
connectionProperties.setProperty(<span class="hljs-string">"useCache"</span>, <span class="hljs-string">"false"</span>);

<span class="hljs-keyword">try</span> (Connection connection = DriverManager.getConnection(url, connectionProperties)) {
  <span class="hljs-comment">// create and execute statements, process result sets, etc</span>
}
</code></pre>
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