Simple Maths Functions

nishmgopla

Hi guys, this is my code:

$query1="SELECT Skill_Name, Weight
FROM ID_Table
JOIN Job_ID ON ID_Table.Job_ID = Job_ID.Job_ID
WHERE Job_ID.Job_Name ='$_SESSION[Job_Name]'";

$result1 = mysql_query($query1) or die ("Couldn't execute query.");

while ($row1=mysql_fetch_array($result1))
{
$tblRows1 .= "<tr>";
$tblRows1 .= "<td>{$row1['Skill_Name']}</td>";
$tblRows1 .= "<td>{$row1['Weight']}</td>";
$tblRows1 .= "</tr>\n";

}

$query="SELECT Skill_Name, Score
FROM Person_Skill
JOIN Person_ID ON Person_Skill.Person_ID = Person_ID.Person_ID
WHERE Person_ID.Person_Name ='$_SESSION[Person_Name]'";

$result = mysql_query($query) or die ("Couldn't execute query.");

while ($row=mysql_fetch_array($result))
{
$tblRows .= "<tr>";
$tblRows .= "<td>{$row['Skill_Name']}</td>";
$tblRows .= "<td>{$row['Score']}</td>";
$tblRows .= "</tr>\n";
}

$diff = ($row['Score']-$row1['Weight']);

echo $diff

I keep getting a return of 0 for $diff. Can some please help me on how to carry out the minus function on each skill and weight?

thank you

NogDog

The problem is that once the relevant while() loop is finished, $row will be boolean false, not an array. So you probably want to save the values of interest to their own variables (or a separate array), then use those variables to do the math.

However, if each query can only return one row (which appears to be the intent here?), then there is no need for the while loops in the first place: just check to see if any rows were returned, and if so, fetch them and then do what you will with them. And then again, it may be that everything could be done in a single query, including the arithmetic.