@echo off
REM generate SQL script to get date in correct format:
echo select 'set my_date=' + str_replace(convert(char(20),getdate(),102),'.','-') >%TEMP%\getDate_yyyy-MM-dd.sql
echo go >>%TEMP%\getDate_yyyy-MM-dd.sql

REM run the SQL script to generate a simple, temporary batch file:
isql -U username -P password -i %TEMP%\getDate_yyyy-MM-dd.sql | findstr set >%TEMP%\set_my_date.bat

REM run the temporary batch file, which will set an environment variable, 'MY_DATE', to contain the date:
call %TEMP%\set_my_date.bat

REM clean up
del /q %TEMP%\set_my_date.bat
del /q %TEMP%\getDate_yyyy-MM-dd.sql

REM this is where you'd actually put code that uses the date, like:
REM md c:\backup\%MY_DATE%
REM copy c:\mystuff\*.* c:\backup\%MY_DATE%