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        <span>Presto 317 Documentation</span></a></h1>
    <h2 class="heading"><span>7.17. Map Functions and Operators</span></h2>
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  <div class="section" id="map-functions-and-operators">
<h1>7.17. Map Functions and Operators</h1>
<div class="section" id="subscript-operator">
<h2>Subscript Operator: []</h2>
<p>The <code class="docutils literal"><span class="pre">[]</span></code> operator is used to retrieve the value corresponding to a given key from a map:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">name_to_age_map</span><span class="p">[</span><span class="s1">&#39;Bob&#39;</span><span class="p">]</span> <span class="k">AS</span> <span class="n">bob_age</span><span class="p">;</span>
</pre></div>
</div>
</div>
<div class="section" id="map-functions">
<h2>Map Functions</h2>
<dl class="function">
<dt>
<code class="descname">cardinality</code><span class="sig-paren">(</span><em>x</em><span class="sig-paren">)</span> &#x2192; bigint</dt>
<dd><p>Returns the cardinality (size) of the map <code class="docutils literal"><span class="pre">x</span></code>.</p>
</dd></dl>

<dl class="function">
<dt>
<code class="descname">element_at</code><span class="sig-paren">(</span><em>map(K</em>, <em>V)</em>, <em>key</em><span class="sig-paren">)</span> &#x2192; V</dt>
<dd><p>Returns value for given <code class="docutils literal"><span class="pre">key</span></code>, or <code class="docutils literal"><span class="pre">NULL</span></code> if the key is not contained in the map.</p>
</dd></dl>

<dl class="function">
<dt id="map">
<code class="descname">map</code><span class="sig-paren">(</span><span class="sig-paren">)</span> &#x2192; map&lt;unknown, unknown&gt;</dt>
<dd><p>Returns an empty map.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="k">map</span><span class="p">();</span> <span class="c1">-- {}</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt>
<code class="descname">map</code><span class="sig-paren">(</span><em>array(K)</em>, <em>array(V)) -&gt; map(K</em>, <em>V</em><span class="sig-paren">)</span></dt>
<dd><p>Returns a map created using the given key/value arrays.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="k">map</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">2</span><span class="p">,</span><span class="mi">4</span><span class="p">]);</span> <span class="c1">-- {1 -&gt; 2, 3 -&gt; 4}</span>
</pre></div>
</div>
<p>See also <a class="reference internal" href="aggregate.html#map_agg" title="map_agg"><code class="xref py py-func docutils literal"><span class="pre">map_agg()</span></code></a> and <a class="reference internal" href="aggregate.html#multimap_agg" title="multimap_agg"><code class="xref py py-func docutils literal"><span class="pre">multimap_agg()</span></code></a> for creating a map as an aggregation.</p>
</dd></dl>

<dl class="function">
<dt id="map_from_entries">
<code class="descname">map_from_entries</code><span class="sig-paren">(</span><em>array(row(K</em>, <em>V))) -&gt; map(K</em>, <em>V</em><span class="sig-paren">)</span></dt>
<dd><p>Returns a map created from the given array of entries.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">map_from_entries</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[(</span><span class="mi">1</span><span class="p">,</span> <span class="s1">&#39;x&#39;</span><span class="p">),</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="s1">&#39;y&#39;</span><span class="p">)]);</span> <span class="c1">-- {1 -&gt; &#39;x&#39;, 2 -&gt; &#39;y&#39;}</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="multimap_from_entries">
<code class="descname">multimap_from_entries</code><span class="sig-paren">(</span><em>array(row(K</em>, <em>V))) -&gt; map(K</em>, <em>array(V)</em><span class="sig-paren">)</span></dt>
<dd><p>Returns a multimap created from the given array of entries. Each key can be associated with multiple values.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">multimap_from_entries</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[(</span><span class="mi">1</span><span class="p">,</span> <span class="s1">&#39;x&#39;</span><span class="p">),</span> <span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="s1">&#39;y&#39;</span><span class="p">),</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="s1">&#39;z&#39;</span><span class="p">)]);</span> <span class="c1">-- {1 -&gt; [&#39;x&#39;, &#39;z&#39;], 2 -&gt; [&#39;y&#39;]}</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="map_entries">
<code class="descname">map_entries</code><span class="sig-paren">(</span><em>map(K</em>, <em>V)) -&gt; array(row(K</em>, <em>V)</em><span class="sig-paren">)</span></dt>
<dd><p>Returns an array of all entries in the given map.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">map_entries</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;x&#39;</span><span class="p">,</span> <span class="s1">&#39;y&#39;</span><span class="p">]));</span> <span class="c1">-- [ROW(1, &#39;x&#39;), ROW(2, &#39;y&#39;)]</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="map_concat">
<code class="descname">map_concat</code><span class="sig-paren">(</span><em>map1(K</em>, <em>V)</em>, <em>map2(K</em>, <em>V)</em>, <em>...</em>, <em>mapN(K</em>, <em>V)) -&gt; map(K</em>, <em>V</em><span class="sig-paren">)</span></dt>
<dd><p>Returns the union of all the given maps. If a key is found in multiple given maps,
that key’s value in the resulting map comes from the last one of those maps.</p>
</dd></dl>

<dl class="function">
<dt id="map_filter">
<code class="descname">map_filter</code><span class="sig-paren">(</span><em>map(K</em>, <em>V)</em>, <em>function(K</em>, <em>V</em>, <em>boolean)) -&gt; map(K</em>, <em>V</em><span class="sig-paren">)</span></dt>
<dd><p>Constructs a map from those entries of <code class="docutils literal"><span class="pre">map</span></code> for which <code class="docutils literal"><span class="pre">function</span></code> returns true:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">map_filter</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[],</span> <span class="nb">ARRAY</span><span class="p">[]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="k">true</span><span class="p">);</span> <span class="c1">-- {}</span>
<span class="k">SELECT</span> <span class="n">map_filter</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">10</span><span class="p">,</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">30</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="k">NULL</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">v</span> <span class="k">IS</span> <span class="k">NOT</span> <span class="k">NULL</span><span class="p">);</span> <span class="c1">-- {10 -&gt; a, 30 -&gt; c}</span>
<span class="k">SELECT</span> <span class="n">map_filter</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;k1&#39;</span><span class="p">,</span> <span class="s1">&#39;k2&#39;</span><span class="p">,</span> <span class="s1">&#39;k3&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">20</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">15</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">v</span> <span class="o">&gt;</span> <span class="mi">10</span><span class="p">);</span> <span class="c1">-- {k1 -&gt; 20, k3 -&gt; 15}</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="map_keys">
<code class="descname">map_keys</code><span class="sig-paren">(</span><em>x(K</em>, <em>V)) -&gt; array(K</em><span class="sig-paren">)</span></dt>
<dd><p>Returns all the keys in the map <code class="docutils literal"><span class="pre">x</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="map_values">
<code class="descname">map_values</code><span class="sig-paren">(</span><em>x(K</em>, <em>V)) -&gt; array(V</em><span class="sig-paren">)</span></dt>
<dd><p>Returns all the values in the map <code class="docutils literal"><span class="pre">x</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="map_zip_with">
<code class="descname">map_zip_with</code><span class="sig-paren">(</span><em>map(K</em>, <em>V1)</em>, <em>map(K</em>, <em>V2)</em>, <em>function(K</em>, <em>V1</em>, <em>V2</em>, <em>V3)) -&gt; map(K</em>, <em>V3</em><span class="sig-paren">)</span></dt>
<dd><p>Merges the two given maps into a single map by applying <code class="docutils literal"><span class="pre">function</span></code> to the pair of values with the same key.
For keys only presented in one map, NULL will be passed as the value for the missing key.</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">map_zip_with</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">]),</span> <span class="c1">-- {1 -&gt; ad, 2 -&gt; be, 3 -&gt; cf}</span>
                    <span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;d&#39;</span><span class="p">,</span> <span class="s1">&#39;e&#39;</span><span class="p">,</span> <span class="s1">&#39;f&#39;</span><span class="p">]),</span>
                    <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v1</span><span class="p">,</span> <span class="n">v2</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">concat</span><span class="p">(</span><span class="n">v1</span><span class="p">,</span> <span class="n">v2</span><span class="p">));</span>
<span class="k">SELECT</span> <span class="n">map_zip_with</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;k1&#39;</span><span class="p">,</span> <span class="s1">&#39;k2&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">]),</span> <span class="c1">-- {k1 -&gt; ROW(1, null), k2 -&gt; ROW(2, 4), k3 -&gt; ROW(null, 9)}</span>
                    <span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;k2&#39;</span><span class="p">,</span> <span class="s1">&#39;k3&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">4</span><span class="p">,</span> <span class="mi">9</span><span class="p">]),</span>
                    <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v1</span><span class="p">,</span> <span class="n">v2</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="p">(</span><span class="n">v1</span><span class="p">,</span> <span class="n">v2</span><span class="p">));</span>
<span class="k">SELECT</span> <span class="n">map_zip_with</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">8</span><span class="p">,</span> <span class="mi">27</span><span class="p">]),</span> <span class="c1">-- {a -&gt; a1, b -&gt; b4, c -&gt; c9}</span>
                    <span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">]),</span>
                    <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v1</span><span class="p">,</span> <span class="n">v2</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">||</span> <span class="k">CAST</span><span class="p">(</span><span class="n">v1</span><span class="o">/</span><span class="n">v2</span> <span class="k">AS</span> <span class="nb">VARCHAR</span><span class="p">));</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="transform_keys">
<code class="descname">transform_keys</code><span class="sig-paren">(</span><em>map(K1</em>, <em>V)</em>, <em>function(K1</em>, <em>V</em>, <em>K2)) -&gt; map(K2</em>, <em>V</em><span class="sig-paren">)</span></dt>
<dd><p>Returns a map that applies <code class="docutils literal"><span class="pre">function</span></code> to each entry of <code class="docutils literal"><span class="pre">map</span></code> and transforms the keys:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">transform_keys</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[],</span> <span class="nb">ARRAY</span><span class="p">[]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">+</span> <span class="mi">1</span><span class="p">);</span> <span class="c1">-- {}</span>
<span class="k">SELECT</span> <span class="n">transform_keys</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">+</span> <span class="mi">1</span><span class="p">);</span> <span class="c1">-- {2 -&gt; a, 3 -&gt; b, 4 -&gt; c}</span>
<span class="k">SELECT</span> <span class="n">transform_keys</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">v</span> <span class="o">*</span> <span class="n">v</span><span class="p">);</span> <span class="c1">-- {1 -&gt; 1, 4 -&gt; 2, 9 -&gt; 3}</span>
<span class="k">SELECT</span> <span class="n">transform_keys</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">||</span> <span class="k">CAST</span><span class="p">(</span><span class="n">v</span> <span class="k">as</span> <span class="nb">VARCHAR</span><span class="p">));</span> <span class="c1">-- {a1 -&gt; 1, b2 -&gt; 2}</span>
<span class="k">SELECT</span> <span class="n">transform_keys</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">.</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">.</span><span class="mi">4</span><span class="p">]),</span> <span class="c1">-- {one -&gt; 1.0, two -&gt; 1.4}</span>
                      <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;one&#39;</span><span class="p">,</span> <span class="s1">&#39;two&#39;</span><span class="p">])[</span><span class="n">k</span><span class="p">]);</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="transform_values">
<code class="descname">transform_values</code><span class="sig-paren">(</span><em>map(K</em>, <em>V1)</em>, <em>function(K</em>, <em>V1</em>, <em>V2)) -&gt; map(K</em>, <em>V2</em><span class="sig-paren">)</span></dt>
<dd><p>Returns a map that applies <code class="docutils literal"><span class="pre">function</span></code> to each entry of <code class="docutils literal"><span class="pre">map</span></code> and transforms the values:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="n">transform_values</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[],</span> <span class="nb">ARRAY</span><span class="p">[]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">v</span> <span class="o">+</span> <span class="mi">1</span><span class="p">);</span> <span class="c1">-- {}</span>
<span class="k">SELECT</span> <span class="n">transform_values</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">10</span><span class="p">,</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">30</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">v</span> <span class="o">+</span> <span class="n">k</span><span class="p">);</span> <span class="c1">-- {1 -&gt; 11, 2 -&gt; 22, 3 -&gt; 33}</span>
<span class="k">SELECT</span> <span class="n">transform_values</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">*</span> <span class="n">k</span><span class="p">);</span> <span class="c1">-- {1 -&gt; 1, 2 -&gt; 4, 3 -&gt; 9}</span>
<span class="k">SELECT</span> <span class="n">transform_values</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">]),</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">k</span> <span class="o">||</span> <span class="k">CAST</span><span class="p">(</span><span class="n">v</span> <span class="k">as</span> <span class="nb">VARCHAR</span><span class="p">));</span> <span class="c1">-- {a -&gt; a1, b -&gt; b2}</span>
<span class="k">SELECT</span> <span class="n">transform_values</span><span class="p">(</span><span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">],</span> <span class="nb">ARRAY</span> <span class="p">[</span><span class="mi">1</span><span class="p">.</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">.</span><span class="mi">4</span><span class="p">]),</span> <span class="c1">-- {1 -&gt; one_1.0, 2 -&gt; two_1.4}</span>
                        <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="k">MAP</span><span class="p">(</span><span class="nb">ARRAY</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">],</span> <span class="nb">ARRAY</span><span class="p">[</span><span class="s1">&#39;one&#39;</span><span class="p">,</span> <span class="s1">&#39;two&#39;</span><span class="p">])[</span><span class="n">k</span><span class="p">]</span> <span class="o">||</span> <span class="s1">&#39;_&#39;</span> <span class="o">||</span> <span class="k">CAST</span><span class="p">(</span><span class="n">v</span> <span class="k">AS</span> <span class="nb">VARCHAR</span><span class="p">));</span>
</pre></div>
</div>
</dd></dl>

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