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hive函数大全：数值与数学相关函数_hive 精度函数

作者：盐析白兔 | 2024-08-11 06:19:44

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hive 精度函数

hive函数官网文档：hive函数官网文档

1.Hive所有内嵌数学函数

Return Type	Name (Signature)	Description
DOUBLE	round(DOUBLE a)	Returns the rounded `BIGINT` value of `a`. 返回对a四舍五入的BIGINT值
DOUBLE	round(DOUBLE a, INT d)	Returns `a` rounded to `d` decimal places. 返回DOUBLE型d的保留n位小数的DOUBLW型的近似值
DOUBLE	bround(DOUBLE a)	Returns the rounded BIGINT value of `a` using HALF_EVEN rounding mode (as of Hive 1.3.0, 2.0.0). Also known as Gaussian rounding or bankers' rounding. Example: bround(2.5) = 2, bround(3.5) = 4. 银行家舍入法（1~4：舍，6~9：进，5->前位数是偶：舍，5->前位数是奇：进）
DOUBLE	bround(DOUBLE a, INT d)	Returns `a` rounded to `d` decimal places using HALF_EVEN rounding mode (as of Hive 1.3.0, 2.0.0). Example: bround(8.25, 1) = 8.2, bround(8.35, 1) = 8.4. 银行家舍入法,保留d位小数
BIGINT	floor(DOUBLE a)	Returns the maximum `BIGINT` value that is equal to or less than `a` 向下取整，最数轴上最接近要求的值的左边的值如：6.10->6 -3.4->-4
BIGINT	ceil(DOUBLE a), ceiling(DOUBLE a)	Returns the minimum BIGINT value that is equal to or greater than `a`. 求其不小于小给定实数的最小整数如：ceil(6) = ceil(6.1)= ceil(6.9) = 6
DOUBLE	rand(), rand(INT seed)	Returns a random number (that changes from row to row) that is distributed uniformly from 0 to 1. Specifying the seed will make sure the generated random number sequence is deterministic. 每行返回一个DOUBLE型随机数seed是随机因子
DOUBLE	exp(DOUBLE a), exp(DECIMAL a)	Returns `ea` where `e` is the base of the natural logarithm. Decimal version added in Hive 0.13.0. 返回e的a幂次方， a可为小数
DOUBLE	ln(DOUBLE a), ln(DECIMAL a)	Returns the natural logarithm of the argument `a`. Decimal version added in Hive 0.13.0. 以自然数为底d的对数，a可为小数
DOUBLE	log10(DOUBLE a), log10(DECIMAL a)	Returns the base-10 logarithm of the argument `a`. Decimal version added in Hive 0.13.0. 以10为底d的对数，a可为小数
DOUBLE	log2(DOUBLE a), log2(DECIMAL a)	Returns the base-2 logarithm of the argument `a`. Decimal version added in Hive 0.13.0. 以2为底数d的对数，a可为小数
DOUBLE	log(DOUBLE base, DOUBLE a) log(DECIMAL base, DECIMAL a)	Returns the base-`base` logarithm of the argument `a`. Decimal versions added in Hive 0.13.0. 以base为底的对数，base 与 a都是DOUBLE类型
DOUBLE	pow(DOUBLE a, DOUBLE p), power(DOUBLE a, DOUBLE p)	Returns `ap`. 计算a的p次幂
DOUBLE	sqrt(DOUBLE a), sqrt(DECIMAL a)	Returns the square root of `a`. Decimal version added in Hive 0.13.0. 计算a的平方根
STRING	bin(BIGINT a)	Returns the number in binary format (see http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_bin). 计算二进制a的STRING类型，a为BIGINT类型
STRING	hex(BIGINT a) hex(STRING a) hex(BINARY a)	If the argument is an `INT` or `binary`, `hex` returns the number as a `STRING` in hexadecimal format. Otherwise if the number is a `STRING`, it converts each character into its hexadecimal representation and returns the resulting `STRING`. (Seehttp://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_hex, `BINARY` version as of Hive 0.12.0.) 计算十六进制a的STRING类型，如果a为STRING类型就转换成字符相对应的十六进制
BINARY	unhex(STRING a)	Inverse of hex. Interprets each pair of characters as a hexadecimal number and converts to the byte representation of the number. (`BINARY` version as of Hive 0.12.0, used to return a string.) hex的逆方法
STRING	conv(BIGINT num, INT from_base, INT to_base), conv(STRING num, INT from_base, INT to_base)	Converts a number from a given base to another (see http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_conv). 将GIGINT/STRING类型的num从from_base进制转换成to_base进制
DOUBLE	abs(DOUBLE a)	Returns the absolute value. 计算a的绝对值
INT or DOUBLE	pmod(INT a, INT b), pmod(DOUBLE a, DOUBLE b)	Returns the positive value of `a mod b`. a对b取模
DOUBLE	sin(DOUBLE a), sin(DECIMAL a)	Returns the sine of `a` (`a` is in radians). Decimal version added in Hive 0.13.0. 求a的正弦值
DOUBLE	asin(DOUBLE a), asin(DECIMAL a)	Returns the arc sin of `a` if -1<=a<=1 or NULL otherwise. Decimal version added in Hive 0.13.0. 求d的反正弦值
DOUBLE	cos(DOUBLE a), cos(DECIMAL a)	Returns the cosine of `a` (`a` is in radians). Decimal version added in Hive 0.13.0. 求余弦值
DOUBLE	acos(DOUBLE a), acos(DECIMAL a)	Returns the arccosine of `a` if -1<=a<=1 or NULL otherwise. Decimal version added in Hive 0.13.0. 求反余弦值
DOUBLE	tan(DOUBLE a), tan(DECIMAL a)	Returns the tangent of `a` (`a` is in radians). Decimal version added in Hive 0.13.0. 求正切值
DOUBLE	atan(DOUBLE a), atan(DECIMAL a)	Returns the arctangent of `a`. Decimal version added in Hive 0.13.0. 求反正切值
DOUBLE	degrees(DOUBLE a), degrees(DECIMAL a)	Converts value of `a` from radians to degrees. Decimal version added in Hive 0.13.0. 奖弧度值转换角度值
DOUBLE	radians(DOUBLE a), radians(DOUBLE a)	Converts value of `a` from degrees to radians. Decimal version added in Hive 0.13.0. 将角度值转换成弧度值
INT or DOUBLE	positive(INT a), positive(DOUBLE a)	Returns `a`. 返回a
INT or DOUBLE	negative(INT a), negative(DOUBLE a)	Returns `-a`. 返回a的相反数
DOUBLE or INT	sign(DOUBLE a), sign(DECIMAL a)	Returns the sign of `a` as '1.0' (if `a` is positive) or '-1.0' (if `a` is negative), '0.0' otherwise. The decimal version returns INT instead of DOUBLE. Decimal version added in Hive 0.13.0. 如果a是正数则返回1.0，是负数则返回-1.0，否则返回0.0
DOUBLE	e()	Returns the value of `e`. 数学常数e
DOUBLE	pi()	Returns the value of `pi`. 数学常数pi
BIGINT	factorial(INT a)	Returns the factorial of `a` (as of Hive 1.2.0). Valid `a` is [0..20]. 求a的阶乘
DOUBLE	cbrt(DOUBLE a)	Returns the cube root of `a` double value (as of Hive 1.2.0). 求a的立方根
INT BIGINT	shiftleft(TINYINT\|SMALLINT\|INT a, INT b) shiftleft(BIGINT a, INT b)	Bitwise left shift (as of Hive 1.2.0). Shifts `a` `b` positions to the left. Returns int for tinyint, smallint and int `a`. Returns bigint for bigint `a`. 按位左移
INT BIGINT	shiftright(TINYINT\|SMALLINT\|INT a, INTb) shiftright(BIGINT a, INT b)	Bitwise right shift (as of Hive 1.2.0). Shifts `a` `b` positions to the right. Returns int for tinyint, smallint and int `a`. Returns bigint for bigint `a`. 按拉右移
INT BIGINT	shiftrightunsigned(TINYINT\|SMALLINT\|INTa, INT b), shiftrightunsigned(BIGINT a, INT b)	Bitwise unsigned right shift (as of Hive 1.2.0). Shifts `a` `b` positions to the right. Returns int for tinyint, smallint and int `a`. Returns bigint for bigint `a`. 无符号按位右移（<<<）
T	greatest(T v1, T v2, ...)	Returns the greatest value of the list of values (as of Hive 1.1.0). Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with ">" operator (as of Hive 2.0.0). 求最大值
T	least(T v1, T v2, ...)	Returns the least value of the list of values (as of Hive 1.1.0). Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with "<" operator (as of Hive 2.0.0). 求最小值

2.常用数值计算函数演示

1. 取整函数: round
语法: round(double a)
返回值: BIGINT
说明: 返回double类型的整数值部分（遵循四舍五入）
举例：
hive> select round(3.1415926) from t_fin_demo;
3
hive> select round(3.5) from t_fin_demo;
4
hive> create table t_fin_demo as select round(9542.158) from t_fin_demo;
hive> describe t_fin_demo;
_c0 bigint

2. 指定精度取整函数: round
语法: round(double a, int d)
返回值: DOUBLE
说明: 返回指定精度d的double类型
举例：
hive> select round(3.1415926,4) from t_fin_demo;
3.1416
3. 向下取整函数: floor
语法: floor(double a)
返回值: BIGINT
说明: 返回等于或者小于该double变量的最大的整数


hive> select floor(3.1415926) from t_fin_demo;
           3
hive> select floor(25) from t_fin_demo;
         25
 
hive> select  floor(-25.1233) from t_fin_demo;  
 
         -26

4. 向上取整函数: ceil,与ceiling一样
语法: ceil(double a)
返回值: BIGINT
说明: 返回等于或者大于该double变量的最小的整数
举例：


hive> select ceil(3.1415926) from t_fin_demo;
          4
hive> select ceil(46) from t_fin_demo;
          46
 
hive> select  ceil(-25.1233) from t_fin_demo; 
 
       -25

5. 向上取整函数: ceiling
语法: ceiling(double a)
返回值: BIGINT
说明: 与ceil功能相同
举例：
hive> select ceiling(3.1415926) from t_fin_demo;
        4
hive> select ceiling(46) from t_fin_demo;
        46
6. 取随机数函数: rand
语法: rand(),rand(int seed)
返回值: double
说明: 返回一个0到1范围内的随机数。如果指定种子seed，则会等到一个稳定的随机数序列
举例：
hive> select rand() from t_fin_demo;
        0.5577432776034763
hive> select rand() from t_fin_demo;
        0.6638336467363424
hive> select rand(100) from t_fin_demo;
        0.7220096548596434
hive> select rand(100) from t_fin_demo;
        0.7220096548596434
7. 自然指数函数: exp
语法: exp(double a)
返回值: double
说明: 返回自然对数e的a次方
举例：
hive> select exp(2) from t_fin_demo;
        7.38905609893065
自然对数函数: ln
语法: ln(double a)
返回值: double
说明: 返回a的自然对数
举例：
hive> select ln(7.38905609893065) from t_fin_demo;
        2.0
9. 以2为底对数函数: log2
语法: log2(double a)
返回值: double
说明: 返回以2为底的a的对数
举例：
hive> select log2(8) from t_fin_demo;
        3.0
10. 对数函数: log
语法: log(double base, double a)
返回值: double
说明: 返回以base为底的a的对数
举例：
hive> select log(4,256) from t_fin_demo;
        4.0
11. 幂运算函数: pow
语法: pow(double a, double p)
返回值: double
说明: 返回a的p次幂
举例：
hive> select pow(2,4) from t_fin_demo;
        16.0
12. 幂运算函数: power
语法: power(double a, double p)
返回值: double
说明: 返回a的p次幂,与pow功能相同
举例：
hive> select power(2,4) from t_fin_demo;
        16.0
13. 开平方函数: sqrt
语法: sqrt(double a)
返回值: double
说明: 返回a的平方根
举例：
hive> select sqrt(16) from lxw_dual;
        4.0
14. 二进制函数: bin
语法: bin(BIGINT a)
返回值: string
说明: 返回a的二进制代码表示
举例：
hive> select bin(7) from t_fin_demo;
        111
15. 十六进制函数: hex
语法: hex(BIGINT a)
返回值: string
说明: 如果变量是int类型，那么返回a的十六进制表示；如果变量是string类型，则返回该字符串的十六进制表示
举例：
hive> select hex(17) from t_fin_demo;
        11
hive> select hex(‘abc’) from t_fin_demo;
        616263
16. 反转十六进制函数: unhex
语法: unhex(string a)
返回值: string
说明: 返回该十六进制字符串所代码的字符串
举例：
hive> select unhex(‘616263’) from t_fin_demo;
abc
hive> select unhex(‘11’) from t_fin_demo;
-
hive> select unhex(616263) from t_fin_demo;
abc

17. 进制转换函数: conv
语法: conv(BIGINT num, int from_base, int to_base)
返回值: string
说明: 将数值num从from_base进制转化到to_base进制
举例：
hive> select conv(17,10,16) from t_fin_demo;
        11
hive> select conv(17,10,2) from t_fin_demo;
        10001

18. 绝对值函数: abs
语法: abs(double a) abs(int a)
返回值: double int
说明: 返回数值a的绝对值
举例：
hive> select abs(-3.9) from lxw_dual;
3.9
hive> select abs(10.9) from t_fin_demo;
10.9

19. negative函数: negative
语法: negative(int a), negative(double a)
返回值: int double
说明: 返回-a,取负数
举例：
hive> select negative(-5) from t_fin_demo;
        5

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