Gegevens naar database

<form name="register" action="" method="post">
First name: <input type="text" name="firstname" /><br />
Surname: <input type="text" name="mail" /><br />
Accountname: <input type="text" name="accountname" /><br />
E-mail:<input type="text" name="mail" /><br />
Age: <input type="text" name="age" /><br />
Password: <input type="password" name="password" /><br />
Confirm password<input type="password" name="password1" /><br />
<input type="submit" name="register" value="register" /><br />
</form>

<?php

$db= mysql_connect("localhost", "user", "secret")
or die("Sorry, er kan geen verbinding met de database gemaakt worden,\n, probeer het later
opnieuw" . mysql_error());
mysql_select_db("algemeen", $db);
$query= "INSERT INTO gegevens (accountname, password, first name, surname, age, email) 
VALUES ('".$_POST["accountname"]."','".$_POST["password"]."','".$_POST["first name"]."','".$_POST["surname"]."',".$_POST["age"].")";
mysql_query($query) or die (mysql_error());
mysql_close($db);
?>

<form name="register" action="" method="post">
First name: <input type="text" name="firstname" /><br />
Surname: <input type="text" name="mail" /><br />
Accountname: <input type="text" name="accountname" /><br />
E-mail:<input type="text" name="mail" /><br />
Age: <input type="text" name="age" /><br />
Password: <input type="password" name="password" /><br />
Confirm password<input type="password" name="password1" /><br />
<input type="submit" name="register" value="register" /><br />
</form>
 
<?php
 
$db= mysql_connect("localhost", "user", "secret")
or die("Sorry, er kan geen verbinding met de database gemaakt worden,\n, probeer het later
opnieuw" . mysql_error());
mysql_select_db("algemeen", $db);
$query= "INSERT INTO gegevens (accountname, password, first name, surname, age, email) 
VALUES ('".$_POST["accountname"]."','".$_POST["password"]."','".$_POST["first name"]."','".$_POST["surname"]."',".$_POST["age"].")";
mysql_query($query) or die (mysql_error());
mysql_close($db);
?>

$query= "INSERT INTO gegevens (accountname, password, first name, surname, age, email)
VALUES ('".$_POST["accountname"]."','".$_POST["password"]."','".$_POST["first name"]."','".$_POST["surname"]."','".$_POST["age"]."')";

$query= "INSERT INTO gegevens (accountname, password, first name, surname, age, email)
VALUES ('".$_POST["accountname"]."','".$_POST["password"]."','".$_POST["first name"]."','".$_POST["surname"]."','".$_POST["age"]."')";