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copied!<p>The reason why you are seeing <strong>all</strong> phone numbers when you <code>echo "$variabele";</code> <strong>inside</strong> the while loop, is because on each iteration (every time the while loop is re-entered, so to speak) you are echoing the last value of <code>$variabele</code>. And so, it <strong>looks</strong> as though everything was <code>echo</code>'d all at once, when in fact it is <code>echo</code>'d one at a time.</p> <p>You can easily demonstrate this by altering the code to:</p> <pre><code>while($row = mysql_fetch_array($result)) { $variabele = $row['leerling_nummer'] . ","; echo "$variabele" . " | "; } </code></pre> <p>Now, you will see the result is not (as I think you expected):</p> <p><code>0612345637,061231823,061231723, |</code></p> <p>... but:</p> <p><code>0612345637, | 061231823, | 061231723, |</code></p> <p>If what you believed was happening, was <strong>really</strong> happening, then the result would actually be this:</p> <p><code>0612345637, | 0612345637, 061231823, | 0612345637, 061231823, 061231723, |</code></p> <p>If you want to collect all phone numbers in one variable, you'd indeed be best off by using an array, as <a href="https://stackoverflow.com/questions/14020132/get-all-data-from-mysql-row-in-a-variabele#14020154">Mark Baker already proposed</a>, <strong>or</strong> you would have to append each new phone number to the <code>$variabele</code> string, like so:</p> <pre><code>// initiate $variabele as an empty string $variabele = ""; while($row = mysql_fetch_array($result)) { // append the new phone number to $variabele (note .= in stead of =) $variabele .= $row['leerling_nummer'] . ","; } echo $variabele; </code></pre> <p>The only problem with this, is that you'd have to remove the last comma then. There are a variety of ways to do this, or circumvent this, but Mark Baker's solution is much simpler actually.</p> <p>Lastly, I want to make you aware of a nifty MySQL function that allows you to easily concatenate values of a column; this is the function <code>GROUP_CONCAT()</code>. This, however, is probably not useful in your current case, since you are fetching other columns as well. But for future reference, if you only need one column want to concatenate them with a comma, you could do:</p> <pre><code>SELECT GROUP_CONCAT( leerling_nummer ) AS leerling_nummers FROM leerlingen WHERE klas_id='$aan_klas' GROUP BY klas_id </code></pre> <p>After querying the database and then doing <code>$row = mysql_fetch_array($result);</code> all numbers would then be in <code>$row['leerling_nummers']</code>, seperated by a comma, because <code>GROUP_CONCAT()</code> uses a comma as a default separator. In other words: you wouldn't need to loop over rows with PHP anymore; MySQL has already collected everything in one row for you.</p>

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