如何用PHP语言处理数组

Question

<?php

$con = mysqli_connect('localhost', 'root', '');
if(!$con)
{
    die("not ok");
}

mysqli_select_db($con,"uoh");  


$q1 = "SELECT * FROM student_record INNER JOIN degree_plan ON
 student_record.course_number = degree_plan.course_number 
 INNER JOIN courses ON student_record.course_number = 
 courses.course_number where student_record.id  = 201102887 AND degree_plan.major='COE'";

$result = mysqli_query($con , $q1 ) ;
$data = array();
while($row = mysqli_fetch_array($result))
{
    $data[$row["term_no"]][] =  array(
        'code' => $row["code"],
        'grade' => $row["grade"]
    );

}


echo '<table width="200" border="1">';
   echo "<tr>";
   echo "<th>courses</th>";
   echo "<th>terms</th>";
   echo "<th>grades</th>";
   echo "</tr>";

foreach($data as $term=>$otherrow) {
    $count = 0;
    foreach ($otherrow as $data) {
        if($count == 0) {
            echo "<tr>";
            echo "<td>" . $data["code"]. "</td>";
            echo '<td rowspan="'.count($otherrow).'">' . $term. '</td>';
            echo "<td>" . $data["grade"]. "</td>";
            echo "</tr>";
            }

        else 

        {
            echo "<tr>";
            echo "<td>" . $data["code"]. "</td>";
            echo "<td>" . $data["grade"]. "</td>";
            echo "</tr>";
        }
        $count++;
    }
}
echo "</table>";

?>

I have this code and it work very well but I faced problem when I want to add more column . I tried to add fourth column(echo "<td>" . $row["crd"]. "</td>"; ) but there is no result .It give me empty cells. how I can do that?

I want add add this echo "<td>" . $row["crd"]. "</td>"; column to my code.

Answer 1

As mentioned in the comments, there are two errors that have been noticed.

1. You are re-declaring $data in your second foreach loop
2. You don't have $row initiated anywhere, and atempting to echo $row["crd"] will result in an empty cell.

Proposed Solution:

Change the name of the $data value in the foreach loop to $row and hence solve both problems at the same time:

foreach($data as $term=>$otherrow) {
    $count = 0;
    foreach ($otherrow as $row) {
        if($count == 0) {
            echo "<tr>";
            echo "<td>" . $row["code"]. "</td>";
            echo '<td rowspan="'.count($otherrow).'">' . $term. '</td>';
            echo "<td>" . $row["grade"]. "</td>";
            echo "</tr>";
            }

        else 

        {
            echo "<tr>";
            echo "<td>" . $row["code"]. "</td>";
            echo "<td>" . $row["grade"]. "</td>";
            echo "</tr>";
        }
        $count++;
    }
} 

And when you add echo "<td>" . $row["crd"]. "</td>"; now it should echo the value stored in the $row array (as long as the value was extracted from the table in the database in the first place of course).

Let me know if this worked for you.