MySQL数学函数简明总结(3)

时间:2014-09-17 02:56来源:网络整理作者:网络点击: 次

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POW(X,Y)与POWER(X,Y)功能相同，用于返回Ｘ的Ｙ次乘方的结果值复制代码代码如下: mysql select pow(2,2), pow(2,-2), pow(-2,2), pow(-2,-2); +----------+-----------+-----------+-

POW(X,Y)与POWER(X,Y)功能相同，用于返回Ｘ的Ｙ次乘方的结果值

复制代码代码如下:

mysql> select pow(2,2), pow(2,-2), pow(-2,2), pow(-2,-2);
+----------+-----------+-----------+------------+
| pow(2,2) | pow(2,-2) | pow(-2,2) | pow(-2,-2) |
+----------+-----------+-----------+------------+
| 4 | 0.25 | 4 | 0.25 |
+----------+-----------+-----------+------------+

mysql> select power(2,2), power(2,-2), power(-2,2), power(-2,-2);
+------------+-------------+-------------+--------------+
| power(2,2) | power(2,-2) | power(-2,2) | power(-2,-2) |
+------------+-------------+-------------+--------------+
| 4 | 0.25 | 4 | 0.25 |
+------------+-------------+-------------+--------------+

EXP(X): 返回e的Ｘ乘方后的值:

复制代码代码如下:

mysql> select EXP(3), EXP(0), EXP(-3);

+-------------------+--------+---------------------+

| EXP(3)            | EXP(0) | EXP(-3)             |

+-------------------+--------+---------------------+

| 20.08553692318767 |      1 | 0.04978706836786393 |

+-------------------+--------+---------------------+

13. LOG(X)和LOG10(X): 对数运算函数（Ｘ必须为正数），LOG(X)-返回Ｘ的自然对数(X相对于基数e的对数)　LOG10(X)-返回x的基数为10的对数：

复制代码代码如下:

mysql> select LOG(-3), LOG(0), LOG(3), LOG10(-100), LOG10(0), LOG10(100);

+---------+--------+--------------------+-------------+----------+------------+

| LOG(-3) | LOG(0) | LOG(3)             | LOG10(-100) | LOG10(0) | LOG10(100) |

+---------+--------+--------------------+-------------+----------+------------+

|    NULL |   NULL | 1.0986122886681098 |        NULL |     NULL |          2 |

+---------+--------+--------------------+-------------+----------+------------+

14. RADIANS(X) 和 DEGREES(X): 角度与弧度转换函数

复制代码代码如下:

mysql> select RADIANS(90), RADIANS(180), DEGREES(PI()), DEGREES(PI()/2);

+--------------------+-------------------+---------------+-----------------+

| RADIANS(90)        | RADIANS(180)      | DEGREES(PI()) | DEGREES(PI()/2) |

+--------------------+-------------------+---------------+-----------------+

| 1.5707963267948966 | 3.141592653589793 |           180 |              90 |

+--------------------+-------------------+---------------+-----------------+

15. SIN(X), ASIN(X), COS(X), ACOS(X), TAN(X), ATAN(X), COT(X)
SIN(X): 正弦函数，其中Ｘ为弧度值
ASIN(X): 反正弦函数　其中Ｘ必须在－１到１之间