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<h1 class="title">Scalar User Defined Functions (UDFs)</h1>
<h3 id="description">Description</h3>
<p>User-Defined Functions (UDFs) are user-programmable routines that act on one row. This documentation lists the classes that are required for creating and registering UDFs. It also contains examples that demonstrate how to define and register UDFs and invoke them in Spark SQL.</p>
<h3 id="userdefinedfunction">UserDefinedFunction</h3>
<p>To define the properties of a user-defined function, the user can use some of the methods defined in this class.</p>
<ul>
<li>
<p><strong>asNonNullable(): UserDefinedFunction</strong></p>
<p>Updates UserDefinedFunction to non-nullable.</p>
</li>
<li>
<p><strong>asNondeterministic(): UserDefinedFunction</strong></p>
<p>Updates UserDefinedFunction to nondeterministic.</p>
</li>
<li>
<p><strong>withName(name: String): UserDefinedFunction</strong></p>
<p>Updates UserDefinedFunction with a given name.</p>
</li>
</ul>
<h3 id="examples">Examples</h3>
<div class="codetabs">
<div data-lang="scala">
<div class="highlight"><pre class="codehilite"><code><span class="k">import</span> <span class="nn">org.apache.spark.sql.SparkSession</span>
<span class="k">import</span> <span class="nn">org.apache.spark.sql.functions.udf</span>
<span class="k">val</span> <span class="nv">spark</span> <span class="k">=</span> <span class="nc">SparkSession</span>
<span class="o">.</span><span class="py">builder</span><span class="o">()</span>
<span class="o">.</span><span class="py">appName</span><span class="o">(</span><span class="s">"Spark SQL UDF scalar example"</span><span class="o">)</span>
<span class="o">.</span><span class="py">getOrCreate</span><span class="o">()</span>
<span class="c1">// Define and register a zero-argument non-deterministic UDF</span>
<span class="c1">// UDF is deterministic by default, i.e. produces the same result for the same input.</span>
<span class="k">val</span> <span class="nv">random</span> <span class="k">=</span> <span class="nf">udf</span><span class="o">(()</span> <span class="k">=&gt;</span> <span class="nv">Math</span><span class="o">.</span><span class="py">random</span><span class="o">())</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">udf</span><span class="o">.</span><span class="py">register</span><span class="o">(</span><span class="s">"random"</span><span class="o">,</span> <span class="nv">random</span><span class="o">.</span><span class="py">asNondeterministic</span><span class="o">())</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">sql</span><span class="o">(</span><span class="s">"SELECT random()"</span><span class="o">).</span><span class="py">show</span><span class="o">()</span>
<span class="c1">// +-------+</span>
<span class="c1">// |UDF() |</span>
<span class="c1">// +-------+</span>
<span class="c1">// |xxxxxxx|</span>
<span class="c1">// +-------+</span>
<span class="c1">// Define and register a one-argument UDF</span>
<span class="k">val</span> <span class="nv">plusOne</span> <span class="k">=</span> <span class="nf">udf</span><span class="o">((</span><span class="n">x</span><span class="k">:</span> <span class="kt">Int</span><span class="o">)</span> <span class="k">=&gt;</span> <span class="n">x</span> <span class="o">+</span> <span class="mi">1</span><span class="o">)</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">udf</span><span class="o">.</span><span class="py">register</span><span class="o">(</span><span class="s">"plusOne"</span><span class="o">,</span> <span class="n">plusOne</span><span class="o">)</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">sql</span><span class="o">(</span><span class="s">"SELECT plusOne(5)"</span><span class="o">).</span><span class="py">show</span><span class="o">()</span>
<span class="c1">// +------+</span>
<span class="c1">// |UDF(5)|</span>
<span class="c1">// +------+</span>
<span class="c1">// | 6|</span>
<span class="c1">// +------+</span>
<span class="c1">// Define a two-argument UDF and register it with Spark in one step</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">udf</span><span class="o">.</span><span class="py">register</span><span class="o">(</span><span class="s">"strLenScala"</span><span class="o">,</span> <span class="o">(</span><span class="k">_:</span> <span class="kt">String</span><span class="o">).</span><span class="py">length</span> <span class="o">+</span> <span class="o">(</span><span class="k">_:</span> <span class="kt">Int</span><span class="o">))</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">sql</span><span class="o">(</span><span class="s">"SELECT strLenScala('test', 1)"</span><span class="o">).</span><span class="py">show</span><span class="o">()</span>
<span class="c1">// +--------------------+</span>
<span class="c1">// |strLenScala(test, 1)|</span>
<span class="c1">// +--------------------+</span>
<span class="c1">// | 5|</span>
<span class="c1">// +--------------------+</span>
<span class="c1">// UDF in a WHERE clause</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">udf</span><span class="o">.</span><span class="py">register</span><span class="o">(</span><span class="s">"oneArgFilter"</span><span class="o">,</span> <span class="o">(</span><span class="n">n</span><span class="k">:</span> <span class="kt">Int</span><span class="o">)</span> <span class="k">=&gt;</span> <span class="o">{</span> <span class="n">n</span> <span class="o">&gt;</span> <span class="mi">5</span> <span class="o">})</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">range</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">10</span><span class="o">).</span><span class="py">createOrReplaceTempView</span><span class="o">(</span><span class="s">"test"</span><span class="o">)</span>
<span class="nv">spark</span><span class="o">.</span><span class="py">sql</span><span class="o">(</span><span class="s">"SELECT * FROM test WHERE oneArgFilter(id)"</span><span class="o">).</span><span class="py">show</span><span class="o">()</span>
<span class="c1">// +---+</span>
<span class="c1">// | id|</span>
<span class="c1">// +---+</span>
<span class="c1">// | 6|</span>
<span class="c1">// | 7|</span>
<span class="c1">// | 8|</span>
<span class="c1">// | 9|</span>
<span class="c1">// +---+</span></code></pre></div>
<div><small>Find full example code at "examples/src/main/scala/org/apache/spark/examples/sql/UserDefinedScalar.scala" in the Spark repo.</small></div>
</div>
<div data-lang="java">
<div class="highlight"><pre class="codehilite"><code><span class="kn">import</span> <span class="nn">org.apache.spark.sql.*</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">org.apache.spark.sql.api.java.UDF1</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">org.apache.spark.sql.expressions.UserDefinedFunction</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">static</span> <span class="n">org</span><span class="o">.</span><span class="na">apache</span><span class="o">.</span><span class="na">spark</span><span class="o">.</span><span class="na">sql</span><span class="o">.</span><span class="na">functions</span><span class="o">.</span><span class="na">udf</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">org.apache.spark.sql.types.DataTypes</span><span class="o">;</span>
<span class="nc">SparkSession</span> <span class="n">spark</span> <span class="o">=</span> <span class="nc">SparkSession</span>
<span class="o">.</span><span class="na">builder</span><span class="o">()</span>
<span class="o">.</span><span class="na">appName</span><span class="o">(</span><span class="s">"Java Spark SQL UDF scalar example"</span><span class="o">)</span>
<span class="o">.</span><span class="na">getOrCreate</span><span class="o">();</span>
<span class="c1">// Define and register a zero-argument non-deterministic UDF</span>
<span class="c1">// UDF is deterministic by default, i.e. produces the same result for the same input.</span>
<span class="nc">UserDefinedFunction</span> <span class="n">random</span> <span class="o">=</span> <span class="n">udf</span><span class="o">(</span>
<span class="o">()</span> <span class="o">-&gt;</span> <span class="nc">Math</span><span class="o">.</span><span class="na">random</span><span class="o">(),</span> <span class="nc">DataTypes</span><span class="o">.</span><span class="na">DoubleType</span>
<span class="o">);</span>
<span class="n">random</span><span class="o">.</span><span class="na">asNondeterministic</span><span class="o">();</span>
<span class="n">spark</span><span class="o">.</span><span class="na">udf</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="s">"random"</span><span class="o">,</span> <span class="n">random</span><span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">sql</span><span class="o">(</span><span class="s">"SELECT random()"</span><span class="o">).</span><span class="na">show</span><span class="o">();</span>
<span class="c1">// +-------+</span>
<span class="c1">// |UDF() |</span>
<span class="c1">// +-------+</span>
<span class="c1">// |xxxxxxx|</span>
<span class="c1">// +-------+</span>
<span class="c1">// Define and register a one-argument UDF</span>
<span class="n">spark</span><span class="o">.</span><span class="na">udf</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="s">"plusOne"</span><span class="o">,</span>
<span class="o">(</span><span class="no">UDF1</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Integer</span><span class="o">&gt;)</span> <span class="n">x</span> <span class="o">-&gt;</span> <span class="n">x</span> <span class="o">+</span> <span class="mi">1</span><span class="o">,</span> <span class="nc">DataTypes</span><span class="o">.</span><span class="na">IntegerType</span><span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">sql</span><span class="o">(</span><span class="s">"SELECT plusOne(5)"</span><span class="o">).</span><span class="na">show</span><span class="o">();</span>
<span class="c1">// +----------+</span>
<span class="c1">// |plusOne(5)|</span>
<span class="c1">// +----------+</span>
<span class="c1">// | 6|</span>
<span class="c1">// +----------+</span>
<span class="c1">// Define and register a two-argument UDF</span>
<span class="nc">UserDefinedFunction</span> <span class="n">strLen</span> <span class="o">=</span> <span class="n">udf</span><span class="o">(</span>
<span class="o">(</span><span class="nc">String</span> <span class="n">s</span><span class="o">,</span> <span class="nc">Integer</span> <span class="n">x</span><span class="o">)</span> <span class="o">-&gt;</span> <span class="n">s</span><span class="o">.</span><span class="na">length</span><span class="o">()</span> <span class="o">+</span> <span class="n">x</span><span class="o">,</span> <span class="nc">DataTypes</span><span class="o">.</span><span class="na">IntegerType</span>
<span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">udf</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="s">"strLen"</span><span class="o">,</span> <span class="n">strLen</span><span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">sql</span><span class="o">(</span><span class="s">"SELECT strLen('test', 1)"</span><span class="o">).</span><span class="na">show</span><span class="o">();</span>
<span class="c1">// +------------+</span>
<span class="c1">// |UDF(test, 1)|</span>
<span class="c1">// +------------+</span>
<span class="c1">// | 5|</span>
<span class="c1">// +------------+</span>
<span class="c1">// UDF in a WHERE clause</span>
<span class="n">spark</span><span class="o">.</span><span class="na">udf</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="s">"oneArgFilter"</span><span class="o">,</span>
<span class="o">(</span><span class="no">UDF1</span><span class="o">&lt;</span><span class="nc">Long</span><span class="o">,</span> <span class="nc">Boolean</span><span class="o">&gt;)</span> <span class="n">x</span> <span class="o">-&gt;</span> <span class="n">x</span> <span class="o">&gt;</span> <span class="mi">5</span><span class="o">,</span> <span class="nc">DataTypes</span><span class="o">.</span><span class="na">BooleanType</span><span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">range</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">10</span><span class="o">).</span><span class="na">createOrReplaceTempView</span><span class="o">(</span><span class="s">"test"</span><span class="o">);</span>
<span class="n">spark</span><span class="o">.</span><span class="na">sql</span><span class="o">(</span><span class="s">"SELECT * FROM test WHERE oneArgFilter(id)"</span><span class="o">).</span><span class="na">show</span><span class="o">();</span>
<span class="c1">// +---+</span>
<span class="c1">// | id|</span>
<span class="c1">// +---+</span>
<span class="c1">// | 6|</span>
<span class="c1">// | 7|</span>
<span class="c1">// | 8|</span>
<span class="c1">// | 9|</span>
<span class="c1">// +---+</span></code></pre></div>
<div><small>Find full example code at "examples/src/main/java/org/apache/spark/examples/sql/JavaUserDefinedScalar.java" in the Spark repo.</small></div>
</div>
</div>
<h3 id="related-statements">Related Statements</h3>
<ul>
<li><a href="sql-ref-functions-udf-aggregate.html">User Defined Aggregate Functions (UDAFs)</a></li>
<li><a href="sql-ref-functions-udf-hive.html">Integration with Hive UDFs/UDAFs/UDTFs</a></li>
</ul>
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