php code to sync tables primay key name should be id

db_sync_lib.php

<?php

function coltable($db, $table){
	
	$stmt = $db->prepare("DESC $table");
	$stmt->execute();

	return array_map(function($v){
		return strtolower($v['Field']);
	}, $stmt->fetchAll(PDO::FETCH_ASSOC));
}

function select($db, $cols, $table, $min, $max){
	
	$sql = "SELECT `" . join('`,`',$cols) . "` FROM `$table` WHERE `id`>= :min AND `id`<:max";

	$stmt = $db->prepare($sql);
	$stmt->bindValue(':min', $min);
	$stmt->bindValue(':max', $max);

	$stmt->execute();
	return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

function selectAllWithCol($db, $cols, $table, $dealrow){
	$f = function($db, $table, $act){
		$stmt = $db->prepare("SELECT $act as i FROM $table");
		$stmt->execute();

		$row = $stmt->fetch(PDO::FETCH_ASSOC);
		return $row['i'];
	};

	$min = $f($db, $table, 'min(id)');
	$max = $f($db, $table, 'max(id)');
	$countAsterisk = $f($db, $table, 'count(*)');

	if(!$countAsterisk){
		return;
	}

	$step = max(($max - $min) / $countAsterisk, 500);
	for ($i = $min; $i < $max;) {
		$lower = $i;
		$upper = min($lower + $step, $max);
		$i = $upper + 1;
		foreach(select($db ,$cols, $table, $lower, $upper) as $r){
			$dealrow($r);
		}
	}
}

function selectAll($db, $table, $dealrow){
	$cols = coltable($db, $table);
	return selectAllWithCol($db, $cols, $table, $dealrow);
}

demo.php

<?
// sync 4 tables with
foreach(array('table1','table2','table3','table4') as $t){

	$c = 0;
	$cols = coltable($db, "old_$t");
	selectAll($db, "old_$t",function($r){
		global $cols , $t ,$c;

		$target = "new_$t";
		$db =  .... ; // NEW DB
		$sql = buildinsert($cols, $target);
		$stmt = $db->prepare($sql);
		foreach($r as $k => $v){
			$stmt->bindValue(":$k", $v);
		}
		$stmt->execute();

		echo "$t ->" . $c++ . "\n";
	});

}