echo off

set nowdate=%date:~4,4%%date:~9,2%%date:~12,2%
rem 如果是XP系统,年月日分别为%date:~0,4%%date:~5,2%%date:~8,2%

exp user/password@example file=D:/DataBAK/Data%nowdate%.dmp log=D:/DataBAK/log/Data%nowdate%.log

set day=%date:~12,2%
set month=%date:~9,2%
set /a deldate=%nowdate%-3

if %month% GTR 10 goto :smallmonth
if %month% LEQ 10 goto :bigmonth

:smallmonth
set /a lastmonth=%month%-1
goto :start

:bigmonth
set /a lastmonth=%month%-1
set lastmonth=0%lastmonth%
goto :start

:start
set delmonthdate=%date:~4,4%%lastmonth%

if %day% GTR 3 goto :del
if %day% LEQ 3 goto :delmonth

:del
D:
cd DataBAK
del Data%deldate%.dmp /q
goto :end

:delmonth
D:
cd DataBAK
del Data%delmonthdate%*.dmp /q
goto :end

:end
exit