What is fastest way to update multiple columns in a table from data of another table where updating table column(s) are something?

Question

I have these two queries which work, but they are slow as can be. What is faster, or rather fastest way of doing this?

method 1)

$query = "
    UPDATE list_data_extra 
    INNER JOIN list_data 
    ON (list_data_extra.serial_no = list_data.serial_no) 
    SET 
    list_data_extra.id = list_data.id, 
    list_data_extra.cid = list_data.cid, 
    list_data_extra.first = list_data.first, 
    list_data_extra.last = list_data.last, 
    list_data_extra.tracking_number = list_data.tracking_number 
    WHERE list_data_extra.id='0' AND list_data_extra.cid='0'
    ";

method 2)

$query = "UPDATE list_data_extra
      INNER JOIN list_data USING (serial_no)
      SET list_data_extra.id = list_data.id,
          list_data_extra.cid = list_data.cid,
          list_data_extra.first = list_data.first, 
          list_data_extra.last = list_data.last, 
          list_data_extra.tracking_number = list_data.tracking_number
     WHERE list_data_extra.id='0'
       AND list_data_extra.cid='0'";

Not sure this other method would be faster:

method 3)

$query="SELECT * FROM list_data_extra WHERE id='0' AND cid='0'";
$result=mysql_query($query);
$num_rows = mysql_num_rows($result);
if ($num_rows > 0) {
    while($row=mysql_fetch_array($result)) {
        $querytwo = mysql_fetch_array(mysql_query(
      "SELECT id, cid, first, last, tracking_number
         FROM list_data
        WHERE serial_no='".$row['serial_no']."'"), MYSQL_ASSOC);
        $querythree = "UPDATE list_data_extra
               SET id='".$querytwo["id"]."', cid='".$querytwo["cid"]."',
                   first='".$querytwo["first"]."', last='".$querytwo["last"]."',
                   tracking_number='".$querytwo["tracking_number"]."'";
        mysql_query($querythree);
    }
}

Another thing i tried is this, which is building entire query then executing it all at once, which is a bit faster than above, but still slow as junk. the above is like 9 minutes per 1000 records and this here below is like 5 minutes per 1000.

method 4)

$query="SELECT * FROM list_data_extra WHERE id='0' AND cid='0'";
$result=mysql_query($query);
$num_rows = mysql_num_rows($result);
if ($num_rows > 0) {
    $id_loop = "";
    $cid_loop = "";
    $first_loop = "";
    $last_loop = "";
    $trackingnumber_loop = "";
    $listids = "";
    while($row=mysql_fetch_array($result)) {
        $querytwo = mysql_fetch_array(mysql_query("SELECT id, cid, first, last, tracking_number FROM list_data WHERE serial_no='".$row['serial_no']."'"), MYSQL_ASSOC);
        $id_loop .= "WHEN ".$row['listid']." THEN '".$querytwo["id"]."' ";
        $cid_loop .= "WHEN ".$row['listid']." THEN '".$querytwo["cid"]."' ";
        $first_loop .= "WHEN ".$row['listid']." THEN '".$querytwo["first"]."' ";
        $last_loop .= "WHEN ".$row['listid']." THEN '".$querytwo["last"]."' ";
        $trackingnumber_loop .= "WHEN ".$row['listid']." THEN '".$querytwo["tracking_number"]."' ";
        $listids .= ", ".$row['listid'];
    }
    $listidsb = substr($listids, 2);
    $querythree = "UPDATE list_data_extra
    SET 
    id = CASE listid
        ".$id_loop."
    END,
    cid = CASE listid
        ".$cid_loop."
    END,
    first = CASE listid
        ".$first_loop."
    END,
    last = CASE listid
        ".$last_loop."
    END,
    tracking_number = CASE listid
        ".$trackingnumber_loop."
    END
    WHERE listid IN (".$listidsb.")";
    mysql_query($querythree) or die(mysql_error());
}

Is there a better and faster way to update multiple columns in many records in one table with data from another table?

CREATE TABLE list_data (
    id int(11) NOT NULL AUTO_INCREMENT, 
    cid int(11) NOT NULL, 
    first varchar(255) NOT NULL, 
    last varchar(255) NOT NULL, 
    tracking_number varchar(255) NOT NULL, 
    serial_no varchar(9) NOT NULL, 
    PRIMARY KEY (id)
) ENGINE=MyISAM AUTO_INCREMENT=555555 DEFAULT CHARSET=latin1

Answer 1

Unindexed JOIN and WHERE conditions can be slow, especially if they involve string data; try running these two (they make take a little time to run if the tables are large), and then trying your original query again.

ALTER TABLE list_data 
ADD INDEX serial_idx (serial_no);

ALTER TABLE list_data_extra 
ADD INDEX serial_idx (serial_no);