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17 lines
1.8 KiB
HTML
17 lines
1.8 KiB
HTML
<div class="m-bg">
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<h1>MySQL NOW() 函数</h1>
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<h2>定义和用法</h2> <p>NOW() 返回当前的日期和时间。</p> <h3><b>语法</b></h3> <div class="code notranslate"><pre><code class="language-sql"><div> NOW()</div></code></pre></div> <h3>实例</h3> <p>下面是 SELECT 语句：</p> <div class="code notranslate"><pre><code class="language-sql"><div> SELECT NOW(),CURDATE(),CURTIME()</div></code></pre></div> <p>结果如下所示：</p> <table class="reference notranslate">
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<tr>
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<th align="left" width="34%">NOW()</th> <th align="left" width="33%">CURDATE()</th> <th align="left" width="33%">CURTIME()</th> </tr>
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<tr>
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<td align="left">2008-11-11 12:45:34</td> <td align="left">2008-11-11</td> <td align="left">12:45:34</td> </tr>
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</table>
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<h3>实例</h3> <p>下面的 SQL 创建带有日期时间列（OrderDate）的 "Orders" 表：</p> <div class="code notranslate"><pre><code class="language-sql"><div> CREATE TABLE Orders<br/> (<br/> OrderId int NOT NULL,<br/> ProductName varchar(50) NOT NULL,<br/> OrderDate datetime NOT NULL DEFAULT NOW(),<br/> PRIMARY KEY (OrderId)<br/> )</div></code></pre></div> <p>请注意，OrderDate 列规定 NOW() 作为默认值。作为结果，当您向表中插入行时，当前日期和时间自动插入列中。</p> <p>现在，我们想要在 "Orders" 表中插入一条记录：</p> <div class="code notranslate"><pre><code class="language-sql"><div> INSERT INTO Orders (ProductName) VALUES ('Jarlsberg Cheese')</div></code></pre></div> <p>"Orders" 表将如下所示：</p> <table class="reference notranslate">
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<tr>
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<th align="left">OrderId</th> <th align="left">ProductName</th> <th align="left">OrderDate</th> </tr>
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<tr>
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<td>1</td> <td>Jarlsberg Cheese</td> <td>2008-11-11 13:23:44.657</td> </tr>
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</table>
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