Here is a script to run a sql command just replace the existing query with your truncate. and add script to cron:
Code:
TABLE_NAME=sometable
USER_NAME=someuser
IP_ADDR=localhost
PASSWORD=somepassword
somevar=`echo "select * from <table_name> where <condition>" | mysql -h $IP_ADDR -u $USER_NAME -p$PASSWD $TABLE_NAME `
echo $somevar
