PHP Defining a variable based on calculations using another variable - php

Question

I am trying to setup a subscription site that is based upon the number of people in a table.
Example: If there are less than 1000 people the cost is $Nil, if there are between 1,000 & 2,000 people, cost is $10, if there is between 2,000 & 3,000 people, cost is $20
I can output the $totalpeople no problems but it's where I want to get the $dkpsub that is causing the issues
I must be doing something wrong because I can't get it to work. Here is where I'm having troubles... Any help would be appreciated... Thanks Rog
<?php
$query = "SELECT count(id) as pcount FROM $people_table $wherestr";
$result = tng_query($query);
$row = tng_fetch_assoc( $result );
$totalpeople = $row['pcount'];
tng_free_result($result);
$dkpsub = if {$totalpeople < 1000,'Nil'};
echo "<ul><li><strong>USD$$dkpsub per annum</strong></br></li></ul>";
?>

Answer 1

Update: S. Imp has more detailed answer above
You should separate definition and assignment. PHP manual
<?php
$query = "SELECT count(id) as pcount FROM $people_table $wherestr";
$result = tng_query($query);
$row = tng_fetch_assoc( $result );
$totalpeople = $row['pcount'];
tng_free_result($result);
$dkpsub = 0;
if ($totalpeople < 1000) { $dkpsub ='Nil'; }
elseif ($totalpeople < 2000) { $dkpsub ='10'; }
else { $dkpsub ='20'; }
echo "<ul><li><strong>USD$$dkpsub per annum</strong></br></li></ul>";
?>

Answer 2

First, you should always check the result of a query for errors. If a query fails, you can get yourself into trouble if your code assumes the query always works. I'm not familiar with the tng_query function, but you might want to check into what it does if the query fails.
Secondly, this doesn't look like valid PHP, so I'm guessing you are getting a syntax error:
$dkpsub = if {$totalpeople < 1000,'Nil'};
In your case, it looks like you'll want an if/elseif/else statement -- but I wonder what will happen if $totalpeople is greater than 3000? Anyways, something like this might work up to that point:
//If there are less than 1000 people the cost is $Nil
if ($totalpeople < 1000) {
// are you sure you want to set it to $Nil?>
$cost = $Nil; // do you maybe mean NULL? or 'Nil'? or perhaps 0?
} elseif ($totalpeople >= 1000 && $totalpeople < 2000) {
// if there are between 1,000 & 2,000 people, cost is $10
$cost = 10;
} elseif ($totalpeople >= 2000 && $totalpeople < 3000){
// if there is between 2,000 & 3,000 people, cost is $20
$cost = 20;
} else {
throw new Exception("unexpected total people encountered");
}

Answer 3

So do think this may work?
<?php
$query = "SELECT count(id) as pcount FROM $people_table $wherestr";
$result = tng_query($query);
$row = tng_fetch_assoc( $result );
$totalpeople = $row['pcount'];
tng_free_result($result);
if ($totalpeople < 1000) {
$dkpsub = 'Nil';
} elseif ($totalpeople >= 1000 && $totalpeople < 2000) {
$dkpsub = 10;
} elseif ($totalpeople >= 2000 && $totalpeople < 3000){
$dkpsub = 15;
} else ($totalpeople > 3000){
$dkpsub = 20;
}
echo "<ul><li><strong>USD$$dkpsub per annum</strong></br></li></ul>";
?>