diff --git a/Script.php b/Script.php
index d1110ef..b089078 100644
--- a/Script.php
+++ b/Script.php
@@ -248,7 +248,7 @@ if (!empty($_POST["frm_reset_password"])) {
 
                 // Password Update
                 $hashed_password = hash('sha512', $password);
-                $sql = "UPDATE users_table set HashPassword='$hashed_password' where User_ID=$userid;";
+                $sql = "UPDATE users_table set HashPassword='$hashed_password' where User_ID='$userid';";
                 if ($con->query($sql) === TRUE) {
 
                     error_reporting(0);
@@ -430,7 +430,7 @@ if (!empty($_POST["frm_uploadlab"])) {
 
     $sql = "INSERT INTO `lab_reports_table`(`Course_ID`, `Posted_Date`, `Deadline`, `Instructions`,
                      `Title`, `Attachment_link_1`, `Attachment_link_2`, `Attachment_link_3`, `Attachment_link_4`,Marks,Type) 
-                     VALUES ('$course_id','$date','$deadline','$instructions','$title','$targetfile','$targetfile2','$targetfile3','$targetfile3',$marks,'$type')";
+                     VALUES ('$course_id','$date','$deadline','$instructions','$title','$targetfile','$targetfile2','$targetfile3','$targetfile3','$marks','$type')";
 
     if ($con->query($sql) === TRUE) {
 
@@ -467,7 +467,7 @@ if (!empty($_POST["frm_submitlab"])) {
     $date = date("Y-m-d H:i:s");
 
     // GET UPLOADED FILES
-    $labName = mysqli_query($con, "SELECT * FROM `lab_reports_table` WHERE Lab_Report_ID=$lab_id");
+    $labName = mysqli_query($con, "SELECT * FROM `lab_reports_table` WHERE Lab_Report_ID='$lab_id'");
     while ($row = mysqli_fetch_assoc($labName)) {
         $lab_name = $row['Title'];
         $_SESSION['Sub_Type'] = $row['Type']; // submission type, either Individual or Group
@@ -571,13 +571,13 @@ if (!empty($_POST["frm_submitlab"])) {
         $group_id = 0; // FIXME
     }
 
-    $sql1 = "DELETE FROM lab_report_submissions where Lab_Report_ID=$lab_id and Student_id=$student_id and Course_Group_id=$group_id";
+    $sql1 = "DELETE FROM lab_report_submissions where Lab_Report_ID='$lab_id' and Student_id='$student_id' and Course_Group_id='$group_id'";
     if ($con->query($sql1) === TRUE) {
     }
 
     $sql = "INSERT INTO `lab_report_submissions`(`Submission_Date`, `Lab_Report_ID`, `Student_id`,"
         . " `Course_Group_id`, `Attachment1`, `Notes`, `Attachment2`, `Attachment3`, `Attachment4`, `Status`, `Title`,`Remarking_Reason`)"
-        . " VALUES ('$date',$lab_id,$student_id,$group_id,'$targetfile','$instructions','$targetfile2','$targetfile3','$targetfile4',"
+        . " VALUES ('$date','$lab_id','$student_id','$group_id','$targetfile','$instructions','$targetfile2','$targetfile3','$targetfile4',"
         . "'Pending','$title','')";
 
     if ($con->query($sql) === TRUE) {
@@ -665,7 +665,7 @@ if (!empty($_GET["updatevisibility"])) {
     $header = mysqli_real_escape_string($con, $_GET["header"]);
     $labid = mysqli_real_escape_string($con, $_GET["labid"]);
 
-    $sql = "UPDATE `lab_report_submissions` SET `Visibility`='$status' WHERE Submission_ID=$id
+    $sql = "UPDATE `lab_report_submissions` SET `Visibility`='$status' WHERE Submission_ID='$id'
               ";
 
     if ($con->query($sql) === TRUE) {
@@ -687,7 +687,7 @@ if (!empty($_GET["remarking"])) {
     $status = mysqli_real_escape_string($con, $_GET["status"]);
     $details = mysqli_real_escape_string($con, $_GET["details"]);
 
-    $sql = "UPDATE `lab_report_submissions` SET `Status`='Remarking',Remarking_Reason='$details' WHERE Submission_ID=$id
+    $sql = "UPDATE `lab_report_submissions` SET `Status`='Remarking',Remarking_Reason='$details' WHERE Submission_ID='$id'
               ";
 
     if ($con->query($sql) === TRUE) {
@@ -709,7 +709,7 @@ if (!empty($_GET["creategroup"])) {
     $name = mysqli_real_escape_string($con, $_GET["name"]);
 
     $sql = "INSERT INTO `course_groups_table`(`Group_Name`, 
-                  `Group_Leader`, `Course_id`) VALUES ('$name',$student_id,$id)";
+                  `Group_Leader`, `Course_id`) VALUES ('$name','$student_id','$id')";
 
     if ($con->query($sql) === TRUE) {
 
@@ -719,7 +719,7 @@ if (!empty($_GET["creategroup"])) {
         }
 
         $sql = "INSERT INTO `course_group_members_table`( `Course_Group_id`, `Student_ID`, `Status`) 
-                          VALUES ($gid,$student_id,'Created')";
+                          VALUES ('$gid','$student_id','Created')";
         if ($con->query($sql) === TRUE) {
             $_SESSION["info_ReMarking"] = "Course group Created";
             header("Location: Course.php?url=" . $url);
@@ -746,7 +746,7 @@ if (!empty($_GET["groupinvite"])) {
         header("Location: Course.php?url=" . $url);
     } else {
         $sql = "INSERT INTO `course_group_members_table`( `Course_Group_id`, `Student_ID`, `Status`)
-                      VALUES ($groupid,$student_id,'Invited')";
+                      VALUES ('$groupid','$student_id','Invited')";
     }
 
     if ($con->query($sql) === TRUE) {
@@ -800,10 +800,10 @@ if (!empty($_GET["acceptinvite"])) {
     $groupid = mysqli_real_escape_string($con, $_GET["groupid"]);
 
     if ($action == 1) {
-        $sql = "Update  `course_group_members_table` set Status='Joined' where  Course_Group_id =$groupid and student_id=$student_id 
+        $sql = "Update  `course_group_members_table` set Status='Joined' where  Course_Group_id ='$groupid' and student_id='$student_id' 
                          ";
     } else {
-        $sql = "Delete from  `course_group_members_table`  where  Course_Group_id =$groupid and student_id=$student_id 
+        $sql = "Delete from  `course_group_members_table`  where  Course_Group_id ='$groupid' and student_id='$student_id' 
                          ";
     }
 
@@ -830,11 +830,11 @@ if (!empty($_GET["extenddeadline"])) {
     $deadline = $date . " " . $time;
 
     if ($type == 1) {
-        $sql = "UPDATE `lab_reports_table` SET  `Deadline`='$deadline'  WHERE Lab_Report_ID=$id";
+        $sql = "UPDATE `lab_reports_table` SET  `Deadline`='$deadline'  WHERE Lab_Report_ID='$id'";
     } else {
         $sql = "INSERT INTO `extended_deadlines_table`(`Student_ID`, "
             . "`Lab_Report_ID`, `Extended_Deadline_Date`,"
-            . " `ReasonsForExtension`) VALUES ($stdid,$id,'$deadline','$reason')";
+            . " `ReasonsForExtension`) VALUES ('$stdid','$id','$deadline','$reason')";
     }
 
     if ($con->query($sql) === TRUE) {
@@ -856,7 +856,7 @@ if (!empty($_GET["ignoreremarking"])) {
 
     $subid = mysqli_real_escape_string($con, $_GET["subid"]);
 
-    $sql = "UPDATE lab_report_submissions SET Status='Marked' WHERE Submission_ID=$subid";
+    $sql = "UPDATE lab_report_submissions SET Status='Marked' WHERE Submission_ID='$subid'";
 
     if ($con->query($sql) === TRUE) {
 
@@ -874,7 +874,7 @@ if (!empty($_GET["assignTA"])) {
     $id = mysqli_real_escape_string($con, $_GET["id"]);
     $ta = mysqli_real_escape_string($con, $_GET["ta"]);
 
-    $sql = "INSERT INTO `course_ta`(`Course_ID`, `TA`) VALUES ($id,$ta)";
+    $sql = "INSERT INTO `course_ta`(`Course_ID`, `TA`) VALUES ('$id','$ta')";
 
     if ($con->query($sql) === TRUE) {
 
@@ -893,9 +893,9 @@ if (!empty($_GET["AcceptStudent"])) {
     $rs = mysqli_real_escape_string($con, $_GET["rs"]);
 
     if ($rs == "yes") {
-        $sql = "Update  course_students_table set Status='Joined' Where ID=$id";
+        $sql = "Update  course_students_table set Status='Joined' Where ID='$id'";
     } else {
-        $sql = "Delete FROM  course_students_table Where ID=$id";
+        $sql = "Delete FROM  course_students_table Where ID='$id'";
     }
 
     if ($con->query($sql) === TRUE) {
@@ -931,7 +931,7 @@ if (!empty($_GET["action"])) {
     }
 
     if ($action == "passchange"  && $_SESSION['user_id'] == $uid) {
-        $sql = "UPDATE users_table set Password='$pass' where User_ID=$uid;";
+        $sql = "UPDATE users_table set Password='$pass' where User_ID='$uid';";
         if ($con->query($sql) === TRUE) {
             error_reporting(0);
             echo "Password has been changed";
@@ -945,7 +945,7 @@ if (!empty($_GET["action"])) {
     }
 
     if ($action == "statuschange" && $_SESSION['user_id'] == $uid && ($_SESSION['user_type'] == "Lecturer" || $_SESSION['user_type'] == "Admin")) {
-        $sql = "UPDATE users_table set Status='$status' where User_ID=$uid;";
+        $sql = "UPDATE users_table set Status='$status' where User_ID='$uid';";
         if ($con->query($sql) === TRUE) {
             $_SESSION["info_Admin_Users"] = $type . " user  Status updated successfully ";
             header("Location: Admin.php");
@@ -1018,7 +1018,7 @@ INNER JOIN lab_reports_table on lab_reports_table.Lab_Report_ID=lab_report_submi
 
 INNER JOIN users_table on users_table.Student_ID=lab_report_submissions.Student_id
 
-WHERE lab_report_submissions.Lab_Report_ID=$lab";
+WHERE lab_report_submissions.Lab_Report_ID='$lab'";
 
     $export  = mysqli_query($con, $select);