MySQL常见数值函数简介

拼搏现实的明天。 2022-04-11 10:38 179阅读 0赞

<table> 
 <thead> 
  <tr> 
   <th>函数名</th> 
   <th>用法简介</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>ABS()</td> 
   <td>返回绝对值</td> 
  </tr> 
  <tr> 
   <td>COS()</td> 
   <td>三角函数，类似的还有SIN(),TAN()等</td> 
  </tr> 
  <tr> 
   <td>ACOS()</td> 
   <td>三角函数，类似还有ATAN(),ASIN()等</td> 
  </tr> 
  <tr> 
   <td>CEILING(n)</td> 
   <td>返回大于n的最小整数</td> 
  </tr> 
  <tr> 
   <td>CONV()</td> 
   <td>进制转换</td> 
  </tr> 
  <tr> 
   <td>DIV()</td> 
   <td>除法，返回整除</td> 
  </tr> 
  <tr> 
   <td>FLOOR(n)</td> 
   <td>返回小于n的最大整数</td> 
  </tr> 
  <tr> 
   <td>LN()</td> 
   <td>对数运算</td> 
  </tr> 
  <tr> 
   <td>LOG(m,n)</td> 
   <td>对数运算，m为底数，n为真数</td> 
  </tr> 
  <tr> 
   <td>LOG2()</td> 
   <td>对数运算</td> 
  </tr> 
  <tr> 
   <td>MOD(m,n)</td> 
   <td>求余，m是被除数，n是除数</td> 
  </tr> 
  <tr> 
   <td>POW(m,n)</td> 
   <td>指数运算，m为底数，n为指数</td> 
  </tr> 
  <tr> 
   <td>PI()</td> 
   <td>返回圆周率，默认6位小数，可以通过+0.0000000000方式增加小数位</td> 
  </tr> 
  <tr> 
   <td>RAND()</td> 
   <td>返回0到1之间的随机浮点数</td> 
  </tr> 
  <tr> 
   <td>ROUND(n)</td> 
   <td>返回四舍五入值</td> 
  </tr> 
  <tr> 
   <td>SQRT(n)</td> 
   <td>开平方</td> 
  </tr> 
  <tr> 
   <td>TRUNCATE(m,n)</td> 
   <td>将m的小数截断成n位，采用四舍五入</td> 
  </tr> 
 </tbody> 
</table>

以下列举部分例子：  
**1.CONV**  
语法：CONV(N,from\_base,to\_base)  
用法：将特定数值进行进制转换。

mysql> select conv('a',16,2);
    +----------------+
    | conv('a',16,2) |
    +----------------+
    | 1010           |
    +----------------+
    1 row in set (0.00 sec)

**2.DIV()**

mysql> select 5 div 2,-5 div 2;
    +---------+----------+
    | 5 div 2 | -5 div 2 |
    +---------+----------+
    |       2 |       -2 |
    +---------+----------+
    1 row in set (0.00 sec)

**3.FLOOR()**

mysql> select floor(2.3),floor(-2.3);
    +------------+-------------+
    | floor(2.3) | floor(-2.3) |
    +------------+-------------+
    |          2 |          -3 |
    +------------+-------------+
    1 row in set (0.00 sec)

**4.PI()**

mysql> select pi();
    +----------+
    | pi()     |
    +----------+
    | 3.141593 |
    +----------+
    1 row in set (0.00 sec)
    
    mysql> select pi()+0.00000000000000000;
    +--------------------------+
    | pi()+0.00000000000000000 |
    +--------------------------+
    |      3.14159265358979300 |
    +--------------------------+
    1 row in set (0.00 sec)