Just for a future reference, mysql backup script:

@REM echo off
@REM this script creates a backup of all the mysql databases in the designated directory.
@REM Please provide day of a week as a parameter

set file=d:Mysql_backup%1%_backup
mysqldump -u backuper --all-databases > %file%
7z a %file%.zip %file%
del %file%

-u backuper specifies the mysql user. This user must have a read access to all the databases. Provide a day of the week as a first argument.