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oracle与sql的区别(常用函数)(2)_MySQL

2020-11-09 来源:赴品旅游

ORACLE函数

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value from dual; 1

8.取10为底对数

S:select log10(10) value 1

O:select log(10,10) value from dual; 1

9.取平方

S:select SQUARE(4) value 16

O:select power(4,2) value from dual 16

10.取平方根

S:select SQRT(4) value 2

O:select SQRT(4) value from dual 2

11.求任意数为底的幂S:select power(3,4) value 81 O:select power(3,4) value from dual 81

12.取随机数

S:select rand() value

O:select sys.dbms_random.value(0,1) value from dual;

13.取符号

S:select sign(-8) value -1

O:select sign(-8) value from dual -1
  ----------三角函数相关
14.圆周率S:SELECT PI() value 3.1415926535897931

O:不知道

15.sin,cos,tan 参数都以弧度为单位

例如:select sin(PI()/2) value得到1(SQLServer)

16.Asin,Acos,Atan,Atan2 返回弧度

17.弧度角度互换(SQLServer,Oracle不知道)

DEGREES:弧度-〉角度

RADIANS:角度-〉弧度

---------数值间比较

18. 求集合最大值

S:select max(value) value from

(select 1 value

union

select -2 value

union

select 4 value

union

select 3 value)a

O:select greatest(1,-2,4,3) value from dual

19. 求集合最小值

S:select min(value) value from

(select 1 value

union

select -2 value

union

select 4 value

union

select 3 value)a

O:select least(1,-2,4,3) value from dual

20.如何处理null值(F2中的null以10代替) S:select F1,IsNull(F2,10) value from Tbl O:select F1,nvl(F2,10) value from Tbl

--------字符串函数

21.求字符序号

S:select ascii('a') value

O:select ascii('a') value from dual

22.从序号求字符

S:select char(97) value

O:select chr(97) value from dual

23.连接

S:select '11'+'22'+'33' value

O:select CONCAT('11','22')||33 value from dual

23.子串位置 --返回3 S:select CHARINDEX('s','sdsq',2) value O:select INSTR('sdsq','s',2) value from dual

23.模糊子串的位置 --返回2,参数去掉中间%则返回7 //

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