--日常使用的sql语句和oracle语句，有些相对使用的频率比较高，收藏起来还是比较值得的-- 绝对值 SQL:select abs(-1) valueOracle:select abs(-1) value from dual--  2.取整(大) SQL:select ceiling(-1.001) value Oracle:select ceil(-1.001) value from dual--  3.取整（小） SQL:select floor(-1.001) value Oracle:select floor(-1.001) value from dual-- 4.取整（截取）SQL:select cast(-1.002 as int) value Oracle:select trunc(-1.002) value from dual --  5.四舍五入SQL:select round(1.23456,4) value 1.23460Oracle:select round(1.23456,4) value from dual 1.2346--  6.e为底的幂 SQL:select Exp(1) value 2.7182818284590451 Oracle:select Exp(1) value from dual 2.71828182--  7.取e为底的对数SQL:select log(2.7182818284590451) value 1Oracle:select ln(2.7182818284590451) value from dual; 1
--   8.取10为底对数SQL:select log10(10) value 1Oracle:select log(10,10) value from dual; 1--  9.取平方SQL:select SQUARE(4) value 16Oracle:select power(4,2) value from dual 16--  10.取平方根SQL:select SQRT(4) value 2Oracle:select SQRT(4) value from dual 2--  11.求任意数为底的幂SQL:select power(3,4) value 81Oracle:select power(3,4) value from dual 81--  12.取随机数SQL:select rand() value Oracle:select sys.dbms_random.value(0,1) value from dual;--  13.取符号SQL:select sign(-8) value -1Oracle:select sign(-8) value from dual -1----------数学函数-- 14.圆周率SQL:SELECT PI() value 3.1415926535897931Oracle: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SQL:select max(value) value from (select 1 valueunionselect -2 valueunionselect 4 valueunionselect 3 value)aOracle:select greatest(1,-2,4,3) value from dual--  19. 求集合最小值SQL:select min(value) value from (select 1 valueunionselect -2 valueunionselect 4 valueunionselect 3 value)aOracle:select least(1,-2,4,3) value from dual--  20.如何处理null值(F2中的null以10代替)SQL:select F1,IsNull(F2,10) value from TblOracle:select F1,nvl(F2,10) value from Tbl
--------数值间比较-- 21.求字符序号SQL:select ascii('a') valueOracle:select ascii('a') value from dual--  22.从序号求字符SQL:select char(97) valueOracle:select chr(97) value from dual--  23.连接SQL:select '11'+'22'+'33' valueOracle:select CONCAT('11','22')||33 value from dual--  23.子串位置 --返回3SQL:select CHARINDEX('s','sdsq',2) value Oracle: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7SQL:select patindex('%d%q%','sdsfasdqe') value Oracle:oracle没发现，但是instr可以通过第四霾问 刂瞥鱿执问?BR>  select INSTR('sdsfasdqe','sd',1,2) value from dual 返回6--  24.求子串SQL:select substring('abcd',2,2) value Oracle:select substr('abcd',2,2) value from dual
--   25.子串代替 返回aijklmnefSQL:SELECT STUFF('abcdef', 2, 3, 'ijklmn') valueOracle:SELECT Replace('abcdef', 'bcd', 'ijklmn') value from dual--  26.子串全部替换
  SQL:没发现Oracle:select Translate('fasdbfasegas','fa','我' ) value from dual
--   27.长度SQL:len,datalengthOracle:length--  28.大小写转换 lower,upper--  29.单词首字母大写
  SQL:没发现Oracle:select INITCAP('abcd dsaf df') value from dual
--   30.左补空格（LPAD的第一个参数为空格则同space函数）SQL:select space(10)+'abcd' valueOracle:select LPAD('abcd',14) value from dual
--   31.右补空格（RPAD的第一个参数为空格则同space函数）SQL:select 'abcd'+space(10) valueOracle:select RPAD('abcd',14) value from dual--  32.删除空格SQL:ltrim,rtrimOracle:ltrim,rtrim,trim--  33. 重复字符串SQL:select REPLICATE('abcd',2) value Oracle:没发现-- 34.发音相似性比较(这两个单词返回值一样，发音相同)SQL:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe')Oracle:SELECT SOUNDEX ('Smith'), SOUNDEX ('Smythe') from dual-- SQLServer中用SELECT DIFFERENCE('Smithers', 'Smythers') 比较soundex的差-- 返回0-4，4为同音，1最高--------------日期函数-- 35.系统时间SQL:select getdate() valueOracle:select sysdate value from dual--  36.前后几日-- 直接与整数相加减
--  37.求日期SQL:select convert(char(10),getdate(),20) valueOracle:select trunc(sysdate) value from dualselect to_char(sysdate,'yyyy-mm-dd') value from dual--  38.求时间SQL:select convert(char(8),getdate(),108) valueOracle:select to_char(sysdate,'hh24:mm:ss') value from dual--  39.取日期时间的其他部分SQL:DATEPART 和 DATENAME 函数 （第一个参数决定） Oracle:to_char函数 第二个参数决定--参数---------------------------------下表需要补充year yy, yyyy quarter qq, q (季度)month mm, m (m O无效)dayofyear dy, y (O表星期)day dd, d (d O无效)week wk, ww (wk O无效)weekday dw (O不清楚)Hour hh,hh12,hh24 (hh12,hh24 S无效)minute mi, n (n O无效)second ss, s (s O无效)millisecond ms (O无效)------------------------------------------------ 40.当月最后一天
  SQL:不知道Oracle:select LAST_DAY(sysdate) value from dual
--   41.本星期的某一天（比如星期日）
  SQL:不知道Oracle:SELECT Next_day(sysdate,7) vaule FROM DUAL;
--   42.字符串转时间SQL:可以直接转或者select cast('2004-09-08'as datetime) valueOracle:SELECT To_date('2004-01-05 22:09:38','yyyy-mm-dd hh24-mi-ss') vaule FROM DUAL;-- 43.求两日期某一部分的差（比如秒）SQL:select datediff(ss,getdate(),getdate()+12.3) valueOracle:直接用两个日期相减（比如d1-d2=12.3）SELECT (d1-d2)*24*60*60 vaule FROM DUAL;--  44.根据差值求新的日期（比如分钟）SQL:select dateadd(mi,8,getdate()) valueOracle:SELECT sysdate+8/60/24 vaule FROM DUAL;--  45.求不同时区时间
  SQL:不知道Oracle:SELECT New_time(sysdate,'ydt','gmt' ) vaule FROM DUAL;