CODEWITHSUNDEEP
phpmysqlundefined
Michael Moncayo
Michael Moncayo

Reputation: 21

PHP For Loop receiving a Notice: Undefined Index

I'm trying to write a php script that queries a database for the semesters a user is registered for by first creating a while loop. Then I'm trying to create a for loop in order to determine the name and level of the classes they're registered for.

//USER ID
$id=1;

//SEMESTER QUERY
$qry="SELECT * FROM semesters where mem_id='$id'";
$result=mysqli_query($con, $qry);

    //GRAB VALUES FROM CURRENT SEMESTER
    while ($row=mysqli_fetch_array($result)){
    $semesterID = $row[1];
    echo '<div id="s'.$semesterID.'">';

        //FOR LOOP TO GRAB ROWS['c1'] TO ['c7']
        for ($i = 1; $i <= 7; $i++) 
        {
        $class = $row['c'.$i.''];

            //IF CLASS_ID IS VALID CONTINUE SEARCH
            if ($class!=0){
            $qry="SELECT * FROM allclasses where class_id='$class'";
            $result=mysqli_query($con, $qry);
            $row=mysqli_fetch_array($result);
            $classname = $row[1];
            $classlvl = $row[2];
            echo ''.$classname.' '.$classlvl.'';
            }
        }
    }

Database Information

The semesters table is composed as such:

| mem_id [0] |semnum [1] | semname [2] | c1 [etc...] | c2 | c3 | c4 | c5 | c6 | c7 |

In this php script I'm trying to:

Problem:

The code actually works on the first for loop but afterward it display a Notice: Undefined Index for c2 through c7

I've tried researching a solution but I've only seen this notice with a script trying to receive POST values...and they recommended using isset and checking the variable but I'm not sure how it would apply in this case.

Upvotes: 1

Views: 634

Answers (1)

bish
bish

Reputation: 3419

I think this line causes your trouble

 $row=mysqli_fetch_array($result);

It's in your subloop and you overwrite your $row variable of the outer loop so it's columns are not available in the runs from 2 to 7 anymore. Rename one of them.

Upvotes: 4

Related Questions