MySQL Merge Two Same Struct Tables

merge_two_tables.sh

#!/bin/bash

database=""
from_table=""
dest_table=""
batch_size=5000
last_id=""
user=""
pwd=""

i=0
while [ true ]
do
	t=$(( i*batch_size ))
	echo "last_id:$last_id $i $t"
	sql="REPLACE INTO ${database}.$dest_table SELECT * FROM ${database}.${from_table} where id > $last_id LIMIT ${batch_size}"
        echo $sql
	date
	mysql -u${user} -p${pwd} -e "$sql"
	new_id=`mysql -u${user} -p${pwd} -s -N -e "SELECT id FROM ${database}.${from_table} where id > $last_id LIMIT ${batch_size},1"`
        if [ -z $new_id ]
	then
          echo "done."
	  break
	fi
        last_id=$new_id
	i=$(( i+1 ))
done