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rn S:select patindex("%d%q%","sdsfasdqe") value O:oracle没发现,但是instr可以通过第四个参数控制出现次数select INSTR("sdsfasdqe","sd",1,2) value from dual 返回6
24.求子串S:select substring("abcd",2,2) value O:select substr("abcd",2,2) value from dual
25.子串代替 返回aijklmnef S:SELECT STUFF("abcdef", 2, 3, "ijklmn") value O:SELECT Replace("abcdef", "bcd", "ijklmn") value from dual
26.子串全部替换
S:Replace
O:select Translate("fasdbfasegas","fa","我" ) value from dual
27.长度S:len,datalength
O:length
28.大小写转换 lower,upper
29.单词首字母大写
S:没发现
O: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)
S:select space(10)+"abcd" value
O: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)
S:select "abcd"+space(10) value
O:select RPAD("abcd",14) value from dual
32.删除空格S:ltrim,rtrim O:ltrim,rtrim,trim
33. 重复字符串S:select REPLICATE("abcd",2) value
O: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) S:SELECT SOUNDEX ("Smith"), SOUNDEX ("Smythe") O: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
S:select getdate() value
O:select sysdate value from dual
36.前后几日
直接与整数相加减
37.求日期S:select convert(char(10),getdate(),20) value
O:select trunc(sysdate) value from dual
select to_char(sysdate,"yyyy-mm-dd") value from dual
38.求时间S:select convert(char(8),getdate(),108) value O:select to_char(sysdate,"hh24:mm:ss") value from dual
39.取日期时间的其他部分
S:DATEPART和DATENAME函数(第一个参数决定)
O: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
S:不知道
O:select LAST_DAY(sysdate) value from d
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