Multiply a databasevalue with a result of a loop - php

Question

Ive currently got this code where I have two loops: one which displays all my ToDos and one which counts the amount of hours ive worked on a certain ToDo.
What I want to do is to multiply the ['pris'] (cost pr hour) with the amount of hours ['timer'] from the loop.
echo "<div id='innhold'>";
$db = kobleTil();
$sql = "SELECT * FROM oppdrag";
$resultat = $db->query($sql);
while($nesteRad = $resultat->fetch_assoc()) {
echo "<hr />";
echo "<table id='resultat'>";
echo "<tr><th colspan='7'>" . $nesteRad['navn'] . "</th></tr>";
echo "<tr><td><b>Type</b></td><td><b>Startdato</b></td><td><b>Sluttdato</b></td><td><b>Pris pr. time</b></td><td><b>Aktiv</b></td></tr>";
echo "<tr>";
echo "<td>" . $nesteRad['type'] . "</td>";
echo "<td>" . $nesteRad['startDato'] . "</td>";
echo "<td>" . $nesteRad['sluttDato'] . "</td>";
echo "<td>" . $nesteRad['pris'] . "</td>";
echo "<td>" . $nesteRad['aktiv'] . "</td>";
echo '<td>Se på</td>';
echo '<td>Legg til timer</td>';
echo '<td>Slett</td>';
echo "</tr></table>";
echo "<hr />";
$prisx = $nesteRad['pris'];
}
echo "<a href='lioppdrag.php'><h5>Legg inn nytt oppdrag</h5></a>";
echo "<br />";
echo "<h3>Statistikk - Oppgaver arbeidet mest med<br /></h3>";
$statistikk = "SELECT oppdrag.*, (SELECT SUM(timer) FROM timeregistrering WHERE timeregistrering.oppdrID = oppdrag.oppdrID) AS Timer FROM oppdrag ORDER BY Timer DESC";
$print = $db->query($statistikk);
while($rad = $print->fetch_assoc()) {
$timer = $rad['Timer'] . '00px';
echo "<b>Oppdrag: " . $rad['navn'] ." Antal timer: " . $rad['Timer'] . " </b><br/>";
echo "<img src='firkant.png' id='firkant' width='"; echo $timer; echo "'></img><br/><br/>";
$timerx = $rad['Timer'];
}
echo "</div>";
} else {
echo "<div id='innhold'>";
echo "<a href='index.php'>Logg inn for å se innholdet</a>";
echo "</div>";
}
?>

Answer 1

I'll try to set you in the right direction but without the exact tables I can't give you the exact answer. first I'd do this in SQL before you ever get to PHOP and loops. Think in terms of set's not loops, so group your todo's and sum(timer) for each group. Then you can do another column with the sum(timer)*pris calling it Total. Psuedocode would be something like
select ToDo.Name, sum(working.timer), sum(timer)*ToDo.Pris as Total
from ToDo join working on todo.id = working.todo_id
group by ToDo.Name
(and a where clause to restrict the dates worked probably unless you just want everything)
edit: sorry I'm not sure why the code didn't show up when I first looked at the question and I only saw it after I answered but I still think this might help so take a look and let me know