How to insert a variable in a database which is calculated by 3 form fields

[freiheit80]

Hello all

Im having an issue trying to insert a variable in to a database.
This variable is the math result of 3 fields of the form, a division multiplied by a number.

So far is returning always 0 so i thought you might gime me a hand here

This is the cold below :

// declare variables to be inserted
$venzini_kinisis_1 = ($_REQUEST['15']/$_REQUEST['8']) * $_REQUEST['1'];
$venzini_100ara = ($_REQUEST['16']/$_REQUEST['9']) * $_REQUEST['2'];
$venzini_super_1 = ($_REQUEST['17']/$_REQUEST['10']) * $_REQUEST['3'];
$venzini_95_1 = ($_REQUEST['18']/$_REQUEST['11']) * $_REQUEST['4'];
$venzini_95_2 = ($_REQUEST['19']/$_REQUEST['12']) * $_REQUEST['5'];
$venzini_super_2 = ($_REQUEST['20']/$_REQUEST['13']) * $_REQUEST['6'];
$venzini_kinisis_2 = ($_REQUEST['21']/$_REQUEST['14']) * $_REQUEST['7'];

if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "insert_form")) {
$insertSQL = sprintf("INSERT INTO kiniseis (polisi_kinisis_1, polisi_100aras, polisi_super_1, polisi_95_1, polisi_95_2, polisi_super_2, polisi_kinisis_2) VALUES (%s, %s, %s, %s, %s, %s, %s)",

GetSQLValueString($_POST['".$venzini_kinisis_1"'], "double"),
GetSQLValueString($_POST['".$venzini_100ara"'], "double"),
GetSQLValueString($_POST['".$venzini_super_1"'], "double"),
GetSQLValueString($_POST['".$venzini_95_1"'], "double"),
GetSQLValueString($_POST['".$venzini_95_2"'], "double"),
GetSQLValueString($_POST['".$venzini_super_2"'], "double"),
GetSQLValueString($_POST['".$venzini_kinisis_2"'], "double"));

Thanks in advance

[themarty]

You perform calculations and then use the results of those calculations to access $_POST variables ... it seems unlikely to me that that is really supposed to be in that way.

for example, you do:

$venzini_kinisis_1 = ($_REQUEST['15']/$_REQUEST['8']) * $_REQUEST['1'];
and then later use this:
$_POST['".$venzini_kinisis_1"']
as an argument in a function. There is no guarantee $venzini_kinisis_1 really exists as a key in $_POST

[freiheit80]

You perform calculations and then use the results of those calculations to access $_POST variables ... it seems unlikely to me that that is really supposed to be in that way.

for example, you do:

$venzini_kinisis_1 = ($_REQUEST['15']/$_REQUEST['8']) * $_REQUEST['1'];
and then later use this:
$_POST['".$venzini_kinisis_1"']
as an argument in a function. There is no guarantee $venzini_kinisis_1 really exists as a key in $_POST

So how i should suppose to do it to be sure it exists as a key cause it supposed that exists.The form has already values in it ,numerical i mean.

[themarty]

for example:

$venzini_kinisis_1 = ($_REQUEST['15']/$_REQUEST['8']) * $_REQUEST['1'];
// check the formula and result:
echo $venzini_kinisis_1." = (".$_REQUEST['15']."/".$_REQUEST['8'].") * ".$_REQUEST['1']."<br>\n";
// check if it exists:
if (array_key_exists($venzini_kinisis_1, $_POST))
{
  echo $venzini_kinisis_1." exists in POST<br>\n";
}
else
{
  echo $venzini_kinisis_1." does not exist in POST, which only contains these keys: ".implode(",", array_keys($_POST))."<br>\n";
} 

* untested

[freiheit80]

I made it like this and it worked fine :

 GetSQLValueString(($_POST['15']/$_POST['8']* $_POST['1']), "double"),
                       GetSQLValueString(($_POST['16']/$_POST['9']*$_POST['2']), "double"),
                       GetSQLValueString(($_POST['17']/$_POST['10']*$_POST['3']), "double"),
                       GetSQLValueString(($_POST['18']/$_POST['11']*$_POST['4']), "double"),
                       GetSQLValueString(($_POST['19']/$_POST['12']*$_POST['5']), "double"),
                       GetSQLValueString(($_POST['20']/$_POST['13']*$_POST['6']), "double"),
                       GetSQLValueString(($_POST['21']/$_POST['14']*$_POST['7']), "double")); 

Thanks guys anyway