insert into mysql else update using select? - php

Question

Can someone please help, I'm trying to make this script select the values from my mysql table where appropriate and update them if they exist, and if they don't exist then to insert them instead.
Can someone show me where I'm going wrong thanks.
<?php
require_once("session.php");
require_once("functions.php");
require('_config/connection.php');
session_start();
include '_config/connection.php';
$height_ft = $_POST['height_ft'];
$height_in = $_POST['height_in'];
$weight_st = $_POST['weight_st'];
$weight_lb = $_POST['weight_lb'];
$result = mysql_query("SELECT height_ft FROM ptb_stats WHERE id=".$_SESSION['user_id']."");
$result2 = mysql_query("SELECT height_in FROM ptb_stats WHERE id=".$_SESSION['user_id']."");
$result3 = mysql_query("SELECT weight_st FROM ptb_stats WHERE id=".$_SESSION['user_id']."");
$result4 = mysql_query("SELECT weight_lb FROM ptb_stats WHERE id=".$_SESSION['user_id']."");
if( !$result ) {
echo "The username you entered does not exist";
} else if( $height_ft != mysql_result( $result, 0 ) ) {
echo "";
$sql = mysql_query("UPDATE ptb_stats SET height_ft='$height_ft' WHERE id=".$_SESSION['user_id']."");
$sql = mysql_query("UPDATE ptb_stats SET height_in='$height_in' WHERE id=".$_SESSION['user_id']."");
$sql = mysql_query("UPDATE ptb_stats SET weight_st='$weight_st' WHERE id=".$_SESSION['user_id']."");
$sql = mysql_query("UPDATE ptb_stats SET weight_lb='$weight_lb' WHERE id=".$_SESSION['user_id']."");
mysql_query("INSERT INTO ptb_stats (user_id, height_ft) VALUES (".$_SESSION['user_id'].", ".$height_ft.")");
mysql_query("INSERT INTO ptb_stats (user_id, height_in) VALUES (".$_SESSION['user_id'].", ".$height_in.")");
mysql_query("INSERT INTO ptb_stats (user_id, weight_st) VALUES (".$_SESSION['user_id'].", ".$weight_st.")");
mysql_query("INSERT INTO ptb_stats (user_id, weight_lb) VALUES (".$_SESSION['user_id'].", ".$weight_lb.")");
}
if( $sql ) {
$_SESSION['edit_done']="<div class=\"infobox-edit-done\"><strong>Thank You -</strong> Your Details were changed.</div>";
header("Location: {$_SERVER['HTTP_REFERER']}");
} else {
$_SESSION['edit_done2']="<div class=\"infobox-edit-done\"><strong>Oooops! -</strong> That didn't work. Try again.</div>";
header("Location: {$_SERVER['HTTP_REFERER']}");
}
?>

Answer 1

There is an option in MySQL for an update or insert using ON DUPLICATE KEY UPDATE which may more concisely solve your question.
http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
For you query would look something like:
$sql=mysql_query("INSERT INTO ptb_stats (user_id, height_ft)
VALUES (".mysql_real_escape_string($_SESSION['user_id']).", "
.mysql_real_escape_string($height_ft).")
ON DUPLICATE KEY UPDATE user_id = ".mysql_real_escape_string($_SESSION['user_id']).");