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        <span>Presto 317 Documentation</span></a></h1>
    <h2 class="heading"><span>7.2. Comparison Functions and Operators</span></h2>
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  <div class="section" id="comparison-functions-and-operators">
<h1>7.2. Comparison Functions and Operators</h1>
<div class="section" id="comparison-operators">
<h2>Comparison Operators</h2>
<table border="1" class="docutils">
<colgroup>
<col width="16%" />
<col width="84%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Operator</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal"><span class="pre">&lt;</span></code></td>
<td>Less than</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">&gt;</span></code></td>
<td>Greater than</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">&lt;=</span></code></td>
<td>Less than or equal to</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">&gt;=</span></code></td>
<td>Greater than or equal to</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">=</span></code></td>
<td>Equal</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">&lt;&gt;</span></code></td>
<td>Not equal</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">!=</span></code></td>
<td>Not equal (non-standard but popular syntax)</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="range-operator-between">
<h2>Range Operator: BETWEEN</h2>
<p>The <code class="docutils literal"><span class="pre">BETWEEN</span></code> operator tests if a value is within a specified range.
It uses the syntax <code class="docutils literal"><span class="pre">value</span> <span class="pre">BETWEEN</span> <span class="pre">min</span> <span class="pre">AND</span> <span class="pre">max</span></code>:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="mi">3</span> <span class="k">BETWEEN</span> <span class="mi">2</span> <span class="k">AND</span> <span class="mi">6</span><span class="p">;</span>
</pre></div>
</div>
<p>The statement shown above is equivalent to the following statement:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="mi">3</span> <span class="o">&gt;=</span> <span class="mi">2</span> <span class="k">AND</span> <span class="mi">3</span> <span class="o">&lt;=</span> <span class="mi">6</span><span class="p">;</span>
</pre></div>
</div>
<p>To test if a value does not fall within the specified range
use <code class="docutils literal"><span class="pre">NOT</span> <span class="pre">BETWEEN</span></code>:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="mi">3</span> <span class="k">NOT</span> <span class="k">BETWEEN</span> <span class="mi">2</span> <span class="k">AND</span> <span class="mi">6</span><span class="p">;</span>
</pre></div>
</div>
<p>The statement shown above is equivalent to the following statement:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="mi">3</span> <span class="o">&lt;</span> <span class="mi">2</span> <span class="k">OR</span> <span class="mi">3</span> <span class="o">&gt;</span> <span class="mi">6</span><span class="p">;</span>
</pre></div>
</div>
<p>A <code class="docutils literal"><span class="pre">NULL</span></code> in a <code class="docutils literal"><span class="pre">BETWEEN</span></code> or <code class="docutils literal"><span class="pre">NOT</span> <span class="pre">BETWEEN</span></code> statement is evaluated
using the standard <code class="docutils literal"><span class="pre">NULL</span></code> evaluation rules applied to the equivalent
expression above:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="k">NULL</span> <span class="k">BETWEEN</span> <span class="mi">2</span> <span class="k">AND</span> <span class="mi">4</span><span class="p">;</span> <span class="c1">-- null</span>

<span class="k">SELECT</span> <span class="mi">2</span> <span class="k">BETWEEN</span> <span class="k">NULL</span> <span class="k">AND</span> <span class="mi">6</span><span class="p">;</span> <span class="c1">-- null</span>

<span class="k">SELECT</span> <span class="mi">2</span> <span class="k">BETWEEN</span> <span class="mi">1</span> <span class="k">AND</span> <span class="k">NULL</span><span class="p">;</span> <span class="c1">-- false</span>

<span class="k">SELECT</span> <span class="mi">8</span> <span class="k">BETWEEN</span> <span class="k">NULL</span> <span class="k">AND</span> <span class="mi">6</span><span class="p">;</span> <span class="c1">-- false</span>
</pre></div>
</div>
<p>The <code class="docutils literal"><span class="pre">BETWEEN</span></code> and <code class="docutils literal"><span class="pre">NOT</span> <span class="pre">BETWEEN</span></code> operators can also be used to
evaluate any orderable type.  For example, a <code class="docutils literal"><span class="pre">VARCHAR</span></code>:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="s1">&#39;Paul&#39;</span> <span class="k">BETWEEN</span> <span class="s1">&#39;John&#39;</span> <span class="k">AND</span> <span class="s1">&#39;Ringo&#39;</span><span class="p">;</span> <span class="c1">-- true</span>
</pre></div>
</div>
<p>Not that the value, min, and max parameters to <code class="docutils literal"><span class="pre">BETWEEN</span></code> and <code class="docutils literal"><span class="pre">NOT</span>
<span class="pre">BETWEEN</span></code> must be the same type.  For example, Presto will produce an
error if you ask it if John is between 2.3 and 35.2.</p>
</div>
<div class="section" id="is-null-and-is-not-null">
<h2>IS NULL and IS NOT NULL</h2>
<p>The <code class="docutils literal"><span class="pre">IS</span> <span class="pre">NULL</span></code> and <code class="docutils literal"><span class="pre">IS</span> <span class="pre">NOT</span> <span class="pre">NULL</span></code> operators test whether a value
is null (undefined).  Both operators work for all data types.</p>
<p>Using <code class="docutils literal"><span class="pre">NULL</span></code> with <code class="docutils literal"><span class="pre">IS</span> <span class="pre">NULL</span></code> evaluates to true:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">select</span> <span class="k">NULL</span> <span class="k">IS</span> <span class="k">NULL</span><span class="p">;</span> <span class="c1">-- true</span>
</pre></div>
</div>
<p>But any other constant does not:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="mi">3</span><span class="p">.</span><span class="mi">0</span> <span class="k">IS</span> <span class="k">NULL</span><span class="p">;</span> <span class="c1">-- false</span>
</pre></div>
</div>
</div>
<div class="section" id="is-distinct-from-and-is-not-distinct-from">
<h2>IS DISTINCT FROM and IS NOT DISTINCT FROM</h2>
<p>In SQL a <code class="docutils literal"><span class="pre">NULL</span></code> value signifies an unknown value, so any comparison
involving a <code class="docutils literal"><span class="pre">NULL</span></code> will produce <code class="docutils literal"><span class="pre">NULL</span></code>.  The  <code class="docutils literal"><span class="pre">IS</span> <span class="pre">DISTINCT</span> <span class="pre">FROM</span></code>
and <code class="docutils literal"><span class="pre">IS</span> <span class="pre">NOT</span> <span class="pre">DISTINCT</span> <span class="pre">FROM</span></code> operators treat <code class="docutils literal"><span class="pre">NULL</span></code> as a known value
and both operators guarantee either a true or false outcome even in
the presence of <code class="docutils literal"><span class="pre">NULL</span></code> input:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="k">NULL</span> <span class="k">IS</span> <span class="k">DISTINCT</span> <span class="k">FROM</span> <span class="k">NULL</span><span class="p">;</span> <span class="c1">-- false</span>

<span class="k">SELECT</span> <span class="k">NULL</span> <span class="k">IS</span> <span class="k">NOT</span> <span class="k">DISTINCT</span> <span class="k">FROM</span> <span class="k">NULL</span><span class="p">;</span> <span class="c1">-- true</span>
</pre></div>
</div>
<p>In the example shown above, a <code class="docutils literal"><span class="pre">NULL</span></code> value is not considered
distinct from <code class="docutils literal"><span class="pre">NULL</span></code>.  When you are comparing values which may
include <code class="docutils literal"><span class="pre">NULL</span></code> use these operators to guarantee either a <code class="docutils literal"><span class="pre">TRUE</span></code> or
<code class="docutils literal"><span class="pre">FALSE</span></code> result.</p>
<p>The following truth table demonstrate the handling of <code class="docutils literal"><span class="pre">NULL</span></code> in
<code class="docutils literal"><span class="pre">IS</span> <span class="pre">DISTINCT</span> <span class="pre">FROM</span></code> and <code class="docutils literal"><span class="pre">IS</span> <span class="pre">NOT</span> <span class="pre">DISTINCT</span> <span class="pre">FROM</span></code>:</p>
<table border="1" class="docutils">
<colgroup>
<col width="13%" />
<col width="13%" />
<col width="15%" />
<col width="15%" />
<col width="19%" />
<col width="26%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">a</th>
<th class="head">b</th>
<th class="head">a = b</th>
<th class="head">a &lt;&gt; b</th>
<th class="head">a DISTINCT b</th>
<th class="head">a NOT DISTINCT b</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal"><span class="pre">1</span></code></td>
<td><code class="docutils literal"><span class="pre">1</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">1</span></code></td>
<td><code class="docutils literal"><span class="pre">2</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">1</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">NULL</span></code></td>
<td><code class="docutils literal"><span class="pre">FALSE</span></code></td>
<td><code class="docutils literal"><span class="pre">TRUE</span></code></td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="greatest-and-least">
<h2>GREATEST and LEAST</h2>
<p>These functions are not in the SQL standard, but are a common extension.
Like most other functions in Presto, they return null if any argument is
null. Note that in some other databases, such as PostgreSQL, they only
return null if all arguments are null.</p>
<p>The following types are supported:
<code class="docutils literal"><span class="pre">DOUBLE</span></code>,
<code class="docutils literal"><span class="pre">BIGINT</span></code>,
<code class="docutils literal"><span class="pre">VARCHAR</span></code>,
<code class="docutils literal"><span class="pre">TIMESTAMP</span></code>,
<code class="docutils literal"><span class="pre">TIMESTAMP</span> <span class="pre">WITH</span> <span class="pre">TIME</span> <span class="pre">ZONE</span></code>,
<code class="docutils literal"><span class="pre">DATE</span></code></p>
<dl class="function">
<dt id="greatest">
<code class="descname">greatest</code><span class="sig-paren">(</span><em>value1</em>, <em>value2</em>, <em>...</em>, <em>valueN</em><span class="sig-paren">)</span> &#x2192; [same as input]</dt>
<dd><p>Returns the largest of the provided values.</p>
</dd></dl>

<dl class="function">
<dt id="least">
<code class="descname">least</code><span class="sig-paren">(</span><em>value1</em>, <em>value2</em>, <em>...</em>, <em>valueN</em><span class="sig-paren">)</span> &#x2192; [same as input]</dt>
<dd><p>Returns the smallest of the provided values.</p>
</dd></dl>

</div>
<div class="section" id="quantified-comparison-predicates-all-any-and-some">
<h2>Quantified Comparison Predicates: ALL, ANY and SOME</h2>
<p>The <code class="docutils literal"><span class="pre">ALL</span></code>, <code class="docutils literal"><span class="pre">ANY</span></code> and <code class="docutils literal"><span class="pre">SOME</span></code> quantifiers can be used together with comparison operators in the
following way:</p>
<div class="highlight-none"><div class="highlight"><pre><span></span>expression operator quantifier ( subquery )
</pre></div>
</div>
<p>For example:</p>
<div class="highlight-sql"><div class="highlight"><pre><span></span><span class="k">SELECT</span> <span class="s1">&#39;hello&#39;</span> <span class="o">=</span> <span class="k">ANY</span> <span class="p">(</span><span class="k">VALUES</span> <span class="s1">&#39;hello&#39;</span><span class="p">,</span> <span class="s1">&#39;world&#39;</span><span class="p">);</span> <span class="c1">-- true</span>

<span class="k">SELECT</span> <span class="mi">21</span> <span class="o">&lt;</span> <span class="k">ALL</span> <span class="p">(</span><span class="k">VALUES</span> <span class="mi">19</span><span class="p">,</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">21</span><span class="p">);</span> <span class="c1">-- false</span>

<span class="k">SELECT</span> <span class="mi">42</span> <span class="o">&gt;=</span> <span class="k">SOME</span> <span class="p">(</span><span class="k">SELECT</span> <span class="mi">41</span> <span class="k">UNION</span> <span class="k">ALL</span> <span class="k">SELECT</span> <span class="mi">42</span> <span class="k">UNION</span> <span class="k">ALL</span> <span class="k">SELECT</span> <span class="mi">43</span><span class="p">);</span> <span class="c1">-- true</span>
</pre></div>
</div>
<p>Here are the meanings of some quantifier and comparison operator combinations:</p>
<table border="1" class="docutils">
<colgroup>
<col width="16%" />
<col width="84%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Expression</th>
<th class="head">Meaning</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">=</span> <span class="pre">ALL</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> is equal to all values.</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">&lt;&gt;</span> <span class="pre">ALL</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> doesn’t match any value.</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">&lt;</span> <span class="pre">ALL</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> is smaller than the smallest value.</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">=</span> <span class="pre">ANY</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> is equal to any of the values. This form is equivalent to <code class="docutils literal"><span class="pre">A</span> <span class="pre">IN</span> <span class="pre">(...)</span></code>.</td>
</tr>
<tr class="row-even"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">&lt;&gt;</span> <span class="pre">ANY</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> doesn’t match one or more values.</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal"><span class="pre">A</span> <span class="pre">&lt;</span> <span class="pre">ANY</span> <span class="pre">(...)</span></code></td>
<td>Evaluates to <code class="docutils literal"><span class="pre">true</span></code> when <code class="docutils literal"><span class="pre">A</span></code> is smaller than the biggest value.</td>
</tr>
</tbody>
</table>
<p><code class="docutils literal"><span class="pre">ANY</span></code> and <code class="docutils literal"><span class="pre">SOME</span></code> have the same meaning and can be used interchangeably.</p>
</div>
</div>


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