SQL幂运算 POW() and POWER()函数用法小结
<div id="navCategory"><h5 class="catalogue">目录</h5><ul class="first_class_ul"><li><a href="#_label0">1. 计算整数的幂🎈🎈</a></li><li><a href="#_label1">2. 计算负数的幂🎈🎈</a></li><li><a href="#_label2">3. 计算零的幂🎈🎈</a></li><li><a href="#_label3">4. 计算小数的幂🎈🎈</a></li><li><a href="#_label4">6. 处理 NULL 输入🎈🎈</a></li><li><a href="#_label5">7.实战小练习：🎈🎈🎈🎈</a></li></ul></div><p><code>POW()</code> 和 <code>POWER()</code> —<strong>计算幂运算（即一个数的指定次方）的函数。</strong></p><p><strong>这两个函数是等价的，功能完全相同，只是名字不同。</strong></p>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265469.png" /></p>
<p>POW(base, exponent);</p>
<p>POWER(base, exponent);</p>
<ul><li><code>base</code>：底数。</li><li><code>exponent</code>：指数。</li></ul>
<p><strong>Demo🍕🍕🍕🍕</strong></p>
<p class="maodian"><a name="_label0"></a></p><h2>1. 计算整数的幂🎈🎈</h2>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(2, 3);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265499.png" /></p>
<p class="maodian"><a name="_label1"></a></p><h2>2. 计算负数的幂🎈🎈</h2>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(-2, 3);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265451.png" /></p>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(-3, 4);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265499.png" /></p>
<p><strong>Tips</strong>：<code>(-3)^4 = (-3) * (-3) * (-3) * (-3) = 81</code>（<strong>偶数次方结果为正</strong>）</p>
<p class="maodian"><a name="_label2"></a></p><h2>3. 计算零的幂🎈🎈</h2>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(0, 5);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265488.png" /></p>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(0, 0);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265458.png" /></p>
<p><strong>Tips：</strong>：<strong>在大多数编程语言和数据库中，<code>0^0</code> 通常定义为 <code>1</code>。</strong></p>
<p class="maodian"><a name="_label3"></a></p><h2>4. 计算小数的幂🎈🎈</h2>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(2.5, 2);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265468.png" /></p>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(4, 0.5);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265515.png" /></p>
<p><strong>Tips</strong>：<code>4^0.5 = √4 = 2</code></p>
<p class="maodian"><a name="_label4"></a></p><h2>6. 处理 NULL 输入🎈🎈</h2>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(NULL, 2);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265555.png" /></p>
<div class="jb51code"><pre class="brush:sql;">SELECT POW(2, NULL);
</pre></div>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265511.png" /></p>
<p><strong>Tips：任何数的 NULL 次方都会返回 NULL，因为 NULL 表示未知值。</strong></p>
<p class="maodian"><a name="_label5"></a></p><h2>7.实战小练习：🎈🎈🎈🎈</h2>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265519.png" /></p>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265552.png" /></p>
<p style="text-align:center"><img alt="" src="https://img.jbzj.com/file_images/article/202509/2025090309265571.png" /></p>
頁:
[1]