sql custom functions for date processing ...

The following are some of the sql function to write function processes used in date processing. . .

asciistr () to convert characters to ASCII code, Chinese character will turn into "\ XXXX" format, can be used to exclude characters.

ltrim (rtrim (strdate)) spaces around removed.

ltrim (rtrim (replace (strdate, chr (10), ''))) and to remove the spaces before and after the line feed

to_char (to_date (ltrim (rtrim (strdate)), 'yY-mm-dd hH: mi: ss'), 'yyyy'); conversion to date format, and taken in and to be taken month, day, hour (the MM, DD, HH24, MI, ss)

length (strdate) - length (replace (strdate, '-', '')) to view the location of a character in the string (the string length - replace a character string length)

-------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 the LENGTH (strDate) =  0  or  the UPPER (strDate) = ' NULL '  or  LTRIM ( RTRIM (strDate)) = ' / ' ) the then - negative characters comprising, a value of 0 or is null, and some special characters 
Results: = 0 ;
 the else 
IF (InStr (strDate, ' . ' ) > 0  or the LENGTH ( LTRIM ( RTRIM ( Replace (strDate, CHR ( 10 ), '' )))) =. 4  or length (strDate) - length ( Replace (strDate, ' - ' , '' )) = . 1 ) the then - on the date data is not converted, intercepts 
the IF (dateType =  . 1 ) THEN  
Results: = substr ( LTRIM ( RTRIM ( Replace (strDate, CHR ( 10 ), '' ))), 0 , . 4 ); 
 the END  the IF ;
 the 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