Notice: Undefined index: - php

Question

I have a problem with my code.
if I use select * from $table it's all good but
now with select distinct it shows me
Notice: Undefined index: L_code in /home/lab_users/web_tue25/web_pages/2014-12-09/stats03-04e.php on line 70
and it show the same for all the variables A/A etc.
Can anyone help me find my mistake(s)???
Thank you
<?php
include_once "dbconnect.php";
$sql = "SELECT DISTINCT akexam = '2003-04.e' FROM $table ";
$result = $dblink->query($sql);
if ($result->num_rows !== 0)
{
echo '<table border="1" style="width:100%; border: 1px solid black; border-collapse:collapse; text-align: center;">
<tr bgcolor= #787878>
<th>A/A</th>
<th>ak.εξαμ.</th>
<th>L_code</th>
<th>τ.ε</th>
<th>ck</th>
<th>rb</th>
<th>L_descr</th>
<th>ΔΗΛ</th>
<th>ΣΥΜ</th>
<th>a</th>
<th>b</th>
<th>c</th>
<th>d</th>
<th>e</th>
<th>f</th>
<th>ΣΥΝ</th>
<th>ok</th>
<th>ok%</th>
</tr>';
while($row = $result->fetch_assoc())
{
echo '<tr bgcolor= purple>';
if(strstr($row["L_code"],"241"))
{
echo "<td style= text-align:left>".$row["A/A"]."</td>";
echo "<td style= text-align:left>".$row["akexam"]."</td>";
echo "<td style= text-align:left>".$row["L_code"]."</td>";
echo "<td>".$row["te"]."</td>";
echo "<td> <input type='checkbox' name= 'ch' value='1'></td>";
echo "<td> <input type='radio' name='labs' value='1'></td>";
echo "<td>".$row["L_descr"]."</td>";
echo "<td style= text-align:right>".$row["dhl"]."</td>";
echo "<td style= text-align:right>".$row["sym"]."</td>";
echo "<td style= text-align:right>".$row["a"]."</td>";
echo "<td style= text-align:right>".$row["b"]."</td>";
echo "<td style= color:blue>".$row["c"]."</td>";
echo "<td style= color:blue>".$row["d"]."</td>";
echo "<td style= color:blue>".$row["e"]."</td>";
echo "<td style= color:blue>".$row["f"]."</td>";
echo "<td style= text-align:right>".$row["syn"]."</td>";
echo "<td style= text-align:right>".$row["ok"]."</td>";
echo "<td style= text-align:right>".$row["ok%"].'%';"</td>";
}
else
{
echo '<tr bgcolor= baby blue>';
echo "<td style= text-align:left>".$row["A/A"]."</td>";
echo "<td style= text-align:left>".$row["akexam"]."</td>";
echo "<td style= text-align:left>".$row["L_code"]."</td>";
echo "<td>".$row["te"]."</td>";
echo "<td> <input type='checkbox' name= 'ch' value='1'></td>";
echo "<td> <input type='radio' name='theories' value='1'></td>";
echo "<td>".$row["L_descr"]."</td>";
echo "<td style= text-align:right>".$row["dhl"]."</td>";
echo "<td style= text-align:right>".$row["sym"]."</td>";
echo "<td style= text-align:right>".$row["a"]."</td>";
echo "<td style= text-align:right>".$row["b"]."</td>";
echo "<td style= color:blue>".$row["c"]."</td>";
echo "<td style= color:blue>".$row["d"]."</td>";
echo "<td style= color:blue>".$row["e"]."</td>";
echo "<td style= color:blue>".$row["f"]."</td>";
echo "<td style= text-align:right>".$row["syn"]."</td>";
echo "<td style= text-align:right>".$row["ok"]."</td>";
echo "<td style= text-align:right>".$row["ok%"].'%';"</td>";
}
echo '</tr>';
}
echo '</table>';
}
else
{
echo "0 results";
}

Answer 1

Yuo have to change the query.
if you select distinct akexam, you will found a list of different akexam values in the table. Your rows will be just $row["akexam"]
If you select distinct * you will select all the different rows in the table.
It will look like a normal select but it will discard the rows that are identical (if you have a primary key in the table all the rows are different, i warn you).
So please provide an explanation of why you want to select distinct and i can give you more precise solution.

Answer 2

You have to select each column individually.
SELECT DISTINCT `akexam`, `L_code`, .... /*Fetch other columns*/
FROM `table`
WHERE akexam = '2003-04.e'