1. ABS(x): 返回x的絕對值

代碼如下:

mysql> select ABS(1), ABS(-1), ABS(0);

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

| ABS(1) | ABS(-1) | ABS(0) |

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

| 1 | 1 | 0 |

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

2. PI(): 返回圓周率

代碼如下:

mysql> select PI();

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

| PI() |

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

| 3.141593 |

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

3. SQRT(x): 返回x的平方根，要求（x為非負數(shù)，返回NULL）

代碼如下:

mysql> select SQRT(49), SQRT(0), SQRT(-49);

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

| SQRT(49) | SQRT(0) | SQRT(-49) |

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

| 7 | 0 | NULL |

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

4. MOD(x,y): 求余函數(shù)，返回x被y除后的余數(shù)；對于帶有小數(shù)部分的數(shù)據(jù)值也起作用，它返回除法運算后的精確余數(shù)。

代碼如下:

mysql> select MOD(31,8), MOD(21,-8), MOD(-7,2), MOD(-7,-2), MOD(45.5,6);

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

| MOD(31,8) | MOD(21,-8) | MOD(-7,2) | MOD(-7,-2) | MOD(45.5,6) |

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

| 7 | 5 | -1 | -1 | 3.5 |

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

5. CEIL(X): 返回不小X的最小整數(shù)值，返回值轉(zhuǎn)為一個BIGINT.

代碼如下:

mysql> select CEIL(-3.35), CEIL(3.35);

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

| CEIL(-3.35) | CEIL(3.35) |

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

| -3 | 4 |

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

6. CEILING(X): 同CEIL(X)

代碼如下:

mysql> select CEILING(-3.35), CEILING(3.35);

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

| CEILING(-3.35) | CEILING(3.35) |

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

| -3 | 4 |

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

7. FLOOR(X):返回不大于X的最大整數(shù)值，返回值轉(zhuǎn)為一個BIGINT.

代碼如下:

mysql> select FLOOR(-3.35), FLOOR(3.35);

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

| FLOOR(-3.35) | FLOOR(3.35) |

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

| -4 | 3 |

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

8. RAND()和RAND(X)

RAND(X) 返回一個隨機浮點值，范圍在０～１之間，X為整數(shù)，它被稱作種子值，用來產(chǎn)生重復(fù)序列。即當(dāng)Ｘ值相同時，產(chǎn)生的隨機數(shù)也相同；

代碼如下:

mysql> select RAND(10), RAND(10), RAND(2), RAND(-2);

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

| RAND(10) | RAND(10) | RAND(2) | RAND(-2) |

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

| 0.6570515219653505 | 0.6570515219653505 | 0.6555866465490187 | 0.6548542125661431 |

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

RAND(): 不帶參數(shù)的RAND()每次產(chǎn)生不同０～１之間的隨機數(shù)

代碼如下:

mysql> SELECT RAND(), RAND(), RAND();

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

| RAND() | RAND() | RAND() |

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

| 0.6931893636409094 | 0.5147262984092592 | 0.49406343185721285 |

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

9. ROUND(X)和ROUND(X,Y): 四舍五入函數(shù)，對Ｘ值按照Ｙ進行四舍五入，Ｙ可以省略，默認值為０;若Ｙ不為０，則保留小數(shù)點后面指定Ｙ位。

復(fù)制代碼 代碼如下:mysql> select ROUND(-1.14), ROUND(-1.9), ROUND(1.14), ROUND(1.9);

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

| ROUND(-1.14) | ROUND(-1.9) | ROUND(1.14) | ROUND(1.9) |

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

| -1 | -2 | 1 | 2 |

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

mysql> select ROUND(1.38,1), ROUND(1.38,0), ROUND(232.38,-1), ROUND(232.38,-2);

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

| ROUND(1.38,1) | ROUND(1.38,0) | ROUND(232.38,-1) | ROUND(232.38,-2) |

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

| 1.4 | 1 | 230 | 200 |

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

10. TRUNCATE(X,Y): 與ROUND(X,Y)功能類似，但不進行四舍五入，只進行截取。

代碼如下:

mysql> select TRUNCATE(1.33,1), TRUNCATE(1.99,1), TRUNCATE(1.99,0), TRUNCATE(19.99,-1);

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

| TRUNCATE(1.33,1) | TRUNCATE(1.99,1) | TRUNCATE(1.99,0) | TRUNCATE(19.99,-1) |

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

| 1.3 | 1.9 | 1 | 10 |

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

11. SIGN(X): 返回參數(shù)Ｘ的符號，Ｘ的值為負、零或正數(shù)時返回結(jié)果依次為－１，０或１

復(fù)制代碼 代碼如下:mysql> select SIGN(-21), SIGN(-0),SIGN(0), SIGN(0.0), SIGN(21);

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

| SIGN(-21) | SIGN(-0) | SIGN(0) | SIGN(0.0) | SIGN(21) |

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

| -1 | 0 | 0 | 0 | 1 |

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

12. POW(X,Y), POWER(X,Y)和EXP(X)

POW(X,Y)與POWER(X,Y)功能相同，用于返回Ｘ的Ｙ次乘方的結(jié)果值

復(fù)制代碼 代碼如下: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:

代碼如下:

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): 對數(shù)運算函數(shù)（Ｘ必須為正數(shù)），LOG(X)-返回Ｘ的自然對數(shù)(X相對于基數(shù)e的對數(shù))　LOG10(X)-返回x的基數(shù)為10的對數(shù)：

代碼如下:

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): 角度與弧度轉(zhuǎn)換函數(shù)

代碼如下:

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): 正弦函數(shù)，其中Ｘ為弧度值

ASIN(X): 反正弦函數(shù)　其中Ｘ必須在－１到１之間

COS(X): 余弦函數(shù)，其中Ｘ為弧度值

ACOS(X): 反余弦函數(shù)　其中Ｘ必須在－１到１之間

TAN(X): 正切函數(shù)，其中Ｘ為弧度值

ATAN(X): 反正切函數(shù)，ATAN(X)與TAN(X)互為反函數(shù)

COT(X):　余切函數(shù)，函數(shù)COT和TAN互為倒函數(shù)

代碼如下:

mysql> select SIGN(PI()/2),ASIN(1),COS(PI()), ACOS(-1), TAN(PI()/4), ATAN(1), COT(0.5);

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

| SIGN(PI()/2) | ASIN(1) | COS(PI()) | ACOS(-1) | TAN(PI()/4) | ATAN(1) | COT(0.5) |

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

| 1 | 1.5707963267948966 | -1 | 3.141592653589793 | 0.9999999999999999 | 0.7853981633974483 | 1.830487721712452 |

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

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