使用php脚本备份mysql数据库表时发出问题

I am Trying to get backup of mysql database table using php script below but by executing this script it is creating the backup file but with no data in it .Any idea how to overcome this please help me out. enter image description here

Script

<?php

echo exec('mysqldump -u[root] -p[123456789] -h[localhost] [Android] [houseDetails] --where="addedDate=\'2013-11-22 09:17:28\'"> houseDetails.sql');

?>

Try this:

shell_exec("mysqldump -u root -ppassword db_name table_name --where=\"post_date in ('2011-12-15 06:14:55')\" > /tmp/test.sql");