Writing calculations back to table

[Donovan]

I am working on a grading app for the university I work for.  So far this is what I have:

 

After gathering the grade info I insert to a table

 

$insertgrades = $db->sql_query("INSERT INTO ".$prefix."_tl_course_grades (Course_ID, SOMS_KEY, UID, Academic_Year, Irat_Avg, Grat_Avg, Appex_Avg) SELECT s.Course_ID, g.SOMS_KEY, g.UID, g.Academic_Year, AVG(IRAT_Grade) AS Irat_Avg, AVG(GRAT_Grade) AS Grat_Avg, AVG(Appex_Grade) AS Appex_Avg
FROM ".$prefix."_tl_session_grades g
JOIN ".$prefix."_tl_session s ON (g.Session_ID = s.Session_ID)
JOIN ".$prefix."_tl_courses c ON (s.Course_ID = c.Course_ID)
WHERE c.Course_ID = '$Course_ID'
GROUP BY g.SOMS_KEY");
if (!$insertgrades) {
	echo("<p>Error performing query: " . mysql_error() . "</p>");
	exit();   
	}

 

I then compute another average of Appex and Grat and write that to GRAT_AppEx_Avg.  I don't know if this is correct but it appears to be working.

 

$updategroupavg = $db->sql_query("UPDATE ".$prefix."_tl_course_grades SET GRAT_AppEx_Avg = (SELECT AVG(Grat_Avg + Appex_Avg)/2 AS GRAT_AppEx_Avg)");
if (!$updategroupavg) {
	echo("<p>Error performing query: " . mysql_error() . "</p>");
	exit();   
	}

 

I then select the "weights" to assign for each part of the grade.  Some parts are weighted more than others. 20%, 40% etc.

 

$getweightinfo = $db->sql_query("SELECT * FROM ".$prefix."_tl_class_weights cw JOIN ".$prefix."_tl_weights w ON cw.weight_id = w.weight_id WHERE Class_Year = '$Course_Year'");
if (!$getweightinfo) {
	echo("<p>Error performing query: " . mysql_error() . "</p>");
	exit();   
	}
while($info = $db->sql_fetchrow($getweightinfo)) {
$irat_wt = $info[irat_wt];
$grat_wt = $info[grat_wt];
$appex_wt = $info[appex_wt];
}

 

Then I am trying to compute the Final grade and here is where I need some help.

 

$processfinalgrade = $db->sql_query("SELECT * FROM ".$prefix."_tl_course_grades WHERE Course_ID = '$Course_ID'");
if (!$processfinalgrade) {
	echo("<p>Error performing query: " . mysql_error() . "</p>");
	exit();   
	}
while($row = $db->sql_fetchrow($processfinalgrade)) {
$IRAT_Avg = $row[iRAT_Avg];
$GRAT_Avg = $row[GRAT_Avg];
$Appex_Avg = $row[Appex_Avg];
$Grade = (($IRAT_Avg * $irat_wt) + ($GRAT_Avg * $grat_wt) + ($Appex_Avg * $appex_wt));
}

 

Update the table

 

$updatefinalgrade = $db->sql_query("UPDATE ".$prefix."_tl_course_grades SET Final_Grade = '$Grade' WHERE Course_ID ='$Course_ID'");

 

which is not writing the correct Final grade.  I get a repeating 67%.

 

Any help is appreciated.