SQL Server中【case...end】的用法

这种写法可以用来做区间或等值的判断。

　　2、相当于C#中的switch...case，例：

<span style="color: #008080">1</span> <span style="color: #0000ff">select</span> CName,头衔<span style="color: #808080">=</span><span style="color: #ff00ff">case</span><span style="color: #000000"> CLevel
</span><span style="color: #008080">2</span>                 <span style="color: #0000ff">when</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">A1</span><span style="color: #ff0000">‘</span> <span style="color: #0000ff">then</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">初级程序员</span><span style="color: #ff0000">‘</span>
<span style="color: #008080">3</span>                 <span style="color: #0000ff">when</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">A2</span><span style="color: #ff0000">‘</span> <span style="color: #0000ff">then</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">中级程序员</span><span style="color: #ff0000">‘</span>
<span style="color: #008080">4</span>                 <span style="color: #0000ff">when</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">A3</span><span style="color: #ff0000">‘</span> <span style="color: #0000ff">then</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">高级程序员</span><span style="color: #ff0000">‘</span>
<span style="color: #008080">5</span>                 <span style="color: #0000ff">else</span> <span style="color: #ff0000">‘</span><span style="color: #ff0000">骨灰级大师</span><span style="color: #ff0000">‘</span>
<span style="color: #008080">6</span>             <span style="color: #0000ff">end</span>
<span style="color: #008080">7</span> <span style="color: #0000ff">from</span> Coder

这种写法只能用来做等值的判断。

注意事项：在 case...end 语句中，then后面值的数据类型必须保持一致。

SQL Server中【case...end】的用法

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