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47 lines
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HTML
47 lines
2.0 KiB
HTML
<div class="m-bg">
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<h1>SQL Server DATEADD() 函数</h1>
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<h2>定义和用法</h2> <p>DATEADD() 函数在日期中添加或减去指定的时间间隔。</p> <h3><b>语法</b></h3> <div class="code notranslate"><pre><code class="language-sql"><div> DATEADD(datepart,number,date)</div></code></pre></div> <p>date 参数是合法的日期表达式。number 是您希望添加的间隔数；对于未来的时间，此数是正数，对于过去的时间，此数是负数。</p> <p>datepart 参数可以是下列的值：</p> <table class="reference notranslate">
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<tr>
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<th align="left">datepart</th> <th align="left">缩写</th> </tr>
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<tr>
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<td>年</td> <td>yy, yyyy</td> </tr>
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<tr>
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<td>季度</td> <td>qq, q</td> </tr>
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<tr>
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<td>月</td> <td>mm, m</td> </tr>
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<tr>
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<td>年中的日</td> <td>dy, y</td> </tr>
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<tr>
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<td>日</td> <td>dd, d</td> </tr>
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<tr>
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<td>周</td> <td>wk, ww</td> </tr>
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<tr>
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<td>星期</td> <td>dw, w</td> </tr>
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<tr>
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<td>小时</td> <td>hh</td> </tr>
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<tr>
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<td>分钟</td> <td>mi, n</td> </tr>
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<tr>
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<td>秒</td> <td>ss, s</td> </tr>
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<tr>
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<td>毫秒</td> <td>ms</td> </tr>
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<tr>
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<td>微妙</td> <td>mcs</td> </tr>
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<tr>
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<td>纳秒</td> <td>ns</td> </tr>
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</table>
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<h3><b>实例</b></h3> <p>假设我们有如下的 "Orders" 表：</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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<p>现在，我们想要向 "OrderDate" 添加 45 天，这样就可以找到付款日期。</p> <p>我们使用下面的 SELECT 语句：</p> <div class="code notranslate"><pre><code class="language-sql"><div> SELECT OrderId,DATEADD(day,45,OrderDate) AS OrderPayDate<br/> FROM Orders</div></code></pre></div> <p>结果：</p> <table class="reference notranslate">
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<tr>
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<th align="left">OrderId</th> <th align="left">OrderPayDate</th> </tr>
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<tr>
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<td>1</td> <td>2008-12-26 13:23:44.657</td> </tr>
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</table>
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