SHOW COLUMNS FROM «table»

function columns($table) {

    $columns = array();
    $sql = "desc $table";
    $q = mysql_query($sql);

    while ($r = mysql_fetch_array($q)) {

       $columns[] = $r[0];

    }

    return $columns;

}

function tables_different($table1, $table2) {

  $cols1 = columns($table1);
  $cols2 = columns($table2);

  return count(array_diff($cols1, $cols2)) ? true : false;

}

$sql = "SELECT * FROM tableA WHERE 1"

$results = mysql_fetch_assoc($sql);

$sql = "truncate table tableB";

// run truncate

foreach($result as $update){

   $sql = "Insert into table b VALUES(....)"

   // run insert
}

class MatchTable
{
    var $_table_one_name;
    var $_table_two_name;

    var $_table_one_db_user;
    var $_table_one_db_pass;
    var $_table_one_db_host;
    var $_table_one_db_name;

    var $_table_two_db_user;
    var $_table_two_db_pass;
    var $_table_two_db_host;
    var $_table_two_db_name;

    var $_table_one_columns = array();
    var $_table_two_columns = array();
    var $_table_one_types = array();
    var $_table_two_types = array();

    var $_table_one_link;
    var $_table_two_link;

    var $_isTest;


    function MatchTable($isLive = true)
    {
    	$this->_isTest = !$isLive;
    }

    function matchTables($table1, $table2)
    {
    	$this->_table_one_name = $table1;
    	$this->_table_two_name = $table2;

    	if(isset($this->_table_one_db_pass))
    	{
    		$this->db_connect('ONE');
    	}
    	list($this->_table_one_columns,$this->_table_one_types) = $this->getColumns($this->_table_one_name);

    	if(isset($this->_table_two_db_pass))
    	{
    		$this->db_connect('TWO');
    	}
    	list($this->_table_two_columns,$this->_table_two_types) = $this->getColumns($this->_table_two_name);

    	$this->addAdditionalColumns($this->getAdditionalColumns());
    }

    function setTableOneConnection($host, $user, $pass, $name)
    {
    	$this->_table_one_db_host = $host;
    	$this->_table_one_db_user = $user;
    	$this->_table_one_db_pass = $pass;
    	$this->_table_one_db_name = $name;
    }

    function setTableTwoConnection($host, $user, $pass, $name)
    {
    	$this->_table_two_db_host = $host;
    	$this->_table_two_db_user = $user;
    	$this->_table_two_db_pass = $pass;
    	$this->_table_two_db_name = $name;
    }

    function db_connect($table)
    {
    	switch(strtoupper($table))
    	{
    		case 'ONE':
    			$host = $this->_table_one_db_host;
    			$user = $this->_table_one_db_user;
    			$pass = $this->_table_one_db_pass;
    			$name = $this->_table_one_db_name;
    			$link = $this->_table_one_link = mysql_connect($host, $user, $pass, true);
    			mysql_select_db($name) or die(mysql_error());
    		break;
    		case 'TWO';
    			$host = $this->_table_two_db_host;
    			$user = $this->_table_two_db_user;
    			$pass = $this->_table_two_db_pass;
    			$name = $this->_table_two_db_name;
    			$link = $this->_table_two_link = mysql_connect($host, $user, $pass, true);
    			mysql_select_db($name) or die(mysql_error());
    		break;
    		default:
    			die('Improper parameter in MatchTable->db_connect() expecting "one" or "two".');
    		break;
    	}
    	if (!$link) {
    		die('Could not connect: ' . mysql_error());
    	}
    }

    function getColumns($table_name)
    {
    	$columns = array();
    	$types = array();
    	$qry = 'SHOW COLUMNS FROM '.$table_name;
    	$result = mysql_query($qry) or die(mysql_error());
    	while($row = mysql_fetch_assoc($result))
    	{
    		$field = $row['Field'];
    		$type = $row['Type'];
    		/*
    		$column = array('Field' => $field, 'Type' => $type);
    		array_push($columns, $column);
    		*/
    		$types[$field] = $type;
    		array_push($columns, $field);
    	}
    	$arr = array($columns, $types);
    	return $arr;
    }

    function getAdditionalColumns()
    {
    	$additional = array_diff($this->_table_one_columns,$this->_table_two_columns);
    	return $additional;
    }

    function addAdditionalColumns($additional)
    {
    	$qry = '';
    	foreach($additional as $field)
    	{
    		$qry = 'ALTER TABLE '.$this->_table_two_name.' ADD '.$field.' '.$this->_table_one_types[$field].'; ';

    		if($this->_isTest)
    		{
    			echo $qry.'<br><br>';
    		}
    		else
    		{
    			mysql_query($qry) or die(mysql_error());
    		}
    	}
    }

    /**
     * End of Class
     */
}