sql 自定义对日期进行处理的函数...

以下是在写对日期处理的函数过程中用到的一些sql 函数。。。

asciistr()把字符转换为ASCII码，汉字会转成"\XXXX"格式，可以用来排除汉字.

ltrim(rtrim(strdate)) 去掉前后的空格。

ltrim(rtrim(replace(strdate,chr(10),'')))去掉换行符和前后的空格

to_char(to_date( ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'yyyy'); 转换成日期格式，并取年，也可以取月日时分秒（MM，DD,HH24 ,MI,ss）

length(strdate) - length(replace(strdate,'-',''))查看某个字符在字符串中的位置（字符串长度-替换掉某个字符的字符串长度）

-------oracle

CREATE OR REPLACE FUNCTION RegexpDate(strDate in varchar2,dateType in number) 
RETURN number is results number;
l_new_string VARCHAR2(255);
l_new_date VARCHAR2(255);
BEGIN 
if(instr(asciistr(strdate),'\')>0 or ltrim(rtrim(strdate))='NaN-aN-aN' or LENGTH(strdate) = 0 or UPPER(strdate) ='NULL' or ltrim(rtrim(strdate))='/' ) then--排除包含汉字的，值为0的，或者为null，及一些特殊字符
results:=0;
else
if(instr(strdate,'.')>0 or LENGTH(ltrim(rtrim(replace(strdate,chr(10),''))))=4 or length(strdate) - length(replace(strdate,'-',''))=1) then--对不能转为日期的数据，进行截取
IF( dateType = 1 ) THEN 
results:=substr(ltrim(rtrim(replace(strdate,chr(10),''))),0,4); 
END IF;
IF( dateType = 2) THEN 
results:=substr(ltrim(rtrim(replace(strdate,chr(10),''))),6,1);
END IF;
IF( dateType = 3) THEN 
results:=0;
END IF;
IF( dateType = 4) THEN 
results:=0;
END IF;
IF( dateType = 5) THEN 
results:=0;
END IF;
IF( dateType = 6) THEN 
results:=0;
END IF;
else
IF( dateType = 1 ) THEN 
results:=to_char(to_date( ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'yyyy'); 
END IF;
IF( dateType = 2) THEN 
results:=to_char(to_date(ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'MM'); 
END IF;
IF( dateType = 3 ) THEN
results:=to_char(to_date(ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'DD'); 
END IF;
IF( dateType = 4 ) THEN
results:=to_char(to_date(ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'HH24'); 
END IF;
IF( dateType = 5 ) THEN
results:=to_char(to_date(ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'MI'); 
END IF;
IF( dateType = 6 ) THEN
results:=to_char(to_date(ltrim(rtrim(strdate)),'yY-mm-dd hH:mi:ss'),'ss'); 
END IF;
end if;
end if;
RETURN (results);
END RegexpDate;

 

 

----sql   server   

CREATE FUNCTION RegexpDate(@strDate nvarchar(50), @dateType int)
Returns int
as
BEGIN
DECLARE @result nvarchar(50);
IF( LEN(@strDate) = 0 or UPPER(@strDate) ='NULL' or ascii(@strDate)>127 or left(@strDate,5)='0-0-0' or CHARINDEX('.-',@strDate)>0 or right(@strDate,6)='- :1:1')
begin
SET @result= 0;
end
else
begin 
if(CHARINDEX('年',@strDate)>0)
begin
SET @strDate = REPLACE(REPLACE( REPLACE(@strDate, '年', '-' ), '月', '-' ), '日', '' );
end
if( CHARINDEX('星期',@strDate)>0)
begin
set @strDate=LEFT(@strDate,LEN(@strDate)-3);
end
if(LEN(@strDate) - LEN(REPLACE(@strDate, '-', ''))=4 and RIGHT(@strDate,2)<>'--')
begin
set @strDate=stuff(@strDate, 11, 1, ' ');
set @strDate=stuff(@strDate, 14, 1, ':');
end
if(right(@strDate,4)=':0:0')
begin
set @strDate=ltrim(rtrim(LEFT(@strDate,LEN(@strDate)-6)));
end
if (right(@strDate,2)='-0' or right(@strDate,2)='--'or RIGHT(@strDate,2)='::' or right(@strDate,1)='-')
begin
if(@dateType=1)
begin
set @result=LEFT(@strDate,4);
end
if(@dateType=2)
begin
set @result=SUBSTRING(@strDate,6,1);
end
if(@dateType=3)
begin
set @result=0
end
if(@dateType=4)
begin
set @result=0
end
if(@dateType=5)
begin
set @result=0
end
if(@dateType=6)
begin
set @result=0
end
end
else 
begin
set @strDate=CONVERT(varchar(100), @strDate, 20);    
if(@dateType=1)
begin
set @result=Datename(year, @strDate);
end
if(@dateType=2)
begin
set @result=Datename(Month, @strDate);
end
if(@dateType=3)
begin
set @result=Datename(Day, @strDate);
end
if(@dateType=4)
begin
set @result=Datename(Hour, @strDate);
end
if(@dateType=5)
begin
set @result=Datename(Minute, @strDate);
end
if(@dateType=6)
begin
set @result=Datename(Second, @strDate);
end
end
if(@result='--'or @result='-')
begin
set @result=0;
end    
end
set    @result=CAST(@result AS int );
RETURN @result;
END;
go

--------------mysql

CREATE DEFINER=`root`@`localhost` FUNCTION `RegexpDate`(`strDate` varchar(255),`dateType` int) RETURNS int(11)
BEGIN
DECLARE
l_new_string VARCHAR ( 255 );
DECLARE
l_new_date VARCHAR ( 255 );
DECLARE
result INT;


IF( LENGTH( strdate ) = 0 or UPPER(strdate) ='NULL' ) THEN
SET result = 0;
else
if(locate('年',strDate)>0) then
SET strDate = REPLACE(REPLACE( REPLACE( strDate, '年', '-' ), '月', '-' ), '日', '' );
end if;
if(str_to_date(strDate, '%Y-%m-%d %H:%i:%s')<>'null') then 
set l_new_date=str_to_date(strDate, '%Y-%m-%d %H:%i:%s');
end if;
if(str_to_date(strDate, '%Y.%m.%d %H:%i:%s')<>'null') then
set l_new_date=STR_TO_DATE(strDate,'%Y.%m.%d %H:%i:%s');
end if;
if(str_to_date(strDate, '%Y/%m/%d %H:%i:%s')<>'null') then
set l_new_date=STR_TO_DATE(strDate,'%Y/%m/%d %H:%i:%s');
end if;
SET l_new_string = l_new_date;
/*    IF(locate('年',strDate)>0 ) THEN

SET l_new_string = REPLACE(REPLACE( REPLACE( strDate, '年', '-' ), '月', '-' ), '日', '' );
ELSE 
SET l_new_string = l_new_date;

END IF;*/

IF( dateType = 1 ) THEN
SET result = YEAR( l_new_string );
END IF;
IF( dateType = 2 ) THEN
SET result = MONTH( l_new_string );
END IF;
IF( dateType = 3 ) THEN
SET result = DAY( l_new_string );
END IF;
IF( dateType = 4 ) THEN
SET result = HOUR(l_new_string );
END IF;
IF( dateType = 5 ) THEN
SET result = MINUTE(l_new_string);
END IF;
IF( dateType = 6 ) THEN
SET result = SECOND(l_new_string);
END IF;
end if;
RETURN result;
END