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1、Version1.1codewritewith2007/12//24红色标记为常用数学函数1.绝对值S:selectabs(-1)valueO:selectabs(-1)valuefromdual2.取整(大)S:selectceiling(-1.001)valueO:selectceil(-1.001)valuefromdual3.取整(小)S:selectfloor(-1.001)valueO:selectfloor(-1.001)valuefromdual4.取整(截取)S:selectcast(-1.002asint)valueO:selecttrunc
2、(-1.002)valuefromdual5.四舍五入S:selectround(1.23456,4)value1.23460O:selectround(1.23456,4)valuefromdual1.23466.e为底的幂S:selectExp(1)value2.7182818284590451O:selectExp(1)valuefromdual2.718281827.取e为底的对数S:selectlog(2.7182818284590451)value1O:selectln(2.7182818284590451)valuefromdual;18.取10为
3、底对数S:selectlog10(10)value1O:selectlog(10,10)valuefromdual;19.取平方S:selectSQUARE(4)value16O:selectpower(4,2)valuefromdual1610.取平方根S:selectSQRT(4)value2O:selectSQRT(4)valuefromdual211.求任意数为底的幂S:selectpower(3,4)value81O:selectpower(3,4)valuefromdual8112.取随机数S:selectrand()valueO:selectsys
4、.dbms_random.value(0,1)valuefromdual;13.取符号S:selectsign(-8)value-1O:selectsign(-8)valuefromdual-1三角函数相关14.圆周率S:SELECTPI()value3.1415926535897931O:不知道15.sin,cos,tan参数都以弧度为单位例如:selectsin(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RA
5、DIANS:角度-〉弧度数值间比较18.求集合最大值S:selectmax(value)valuefrom(select1valueunionselect-2valueunionselect4valueunionselect3value)aO:selectgreatest(1,-2,4,3)valuefromdual19.求集合最小值S:selectmin(value)valuefrom(select1valueunionselect-2valueunionselect4valueunionselect3value)aO:selectleast(1,-2,4,3
6、)valuefromdual20.如何处理null值(F2中的null以10代替)S:selectF1,IsNull(F2,10)valuefromTblO:selectF1,nvl(F2,10)valuefromTbl聚合函数SumS:selectsum(列)from表名O:selectsum(列)from表名MaxS:selectmax(列)from表名O:selectmax(列)from表名MinS:selectmin(列)from表名O:selectmin(列)from表名系统函数IsnullS:selectisnull(列,’0’)from表名称O:s
7、electnvl(列,’0’)from表名字符串函数21.求字符序号S:selectascii('a')valueO:selectascii('a')valuefromdual22.从序号求字符S:selectchar(97)valueO:selectchr(97)valuefromdual23.连接S:select'11'+'22'+'33'valueO:selectCONCAT('11','22')
8、
9、33valuefromdual23.子串位置--返回3S:selectCHARINDEX('s','sdsq',2)valueO:selectINSTR('s
10、dsq','s',2)v