This is my table:
I want a query that will retrieve the maximum QID from the table where I specify a Pid. Then I want to take the selected value and add 1 to it. I want this to work even if there is no value on qid where Pid is for example 1 or 2.
For example if the max qid is 1 where pid is 1, I want a code to retrieve the value qid=1 and add 1 to it. Then the new value, "2" in this case, should be stored in a hidden input field. If I, for example, put "WHERE pid=4" in my query and there is no pid=4 in my table, which retrieves a null value from qid, that should also work and the new value should be 1(null + 1 = 1).
I have this but I don't know if it is right. I'm maybe doing something wrong in the query.
<?php
$qu = "SELECT coalesce(max(qid),1) AS id FROM answer_det WHERE pid = '1' ";
$result = $mysqli->query($qu);
if ($result->num_rows > 0) {
while($row = $result->fetch_array()) {
echo "
<form action='insertdilemma.php' method='post'>
<input type='text' name='ans1'>
<input type='hidden' name='qidsend' value='". $row["id"]. "'>
<input type='submit' name='submit' value='Send'>
</form>";
}}
else {
echo "0 results";
}
mysqli_close($mysqli);
?>
I get this error message: Notice: Trying to get property of non-object in C:\xampp\htdocs\wildfire\dilemman.php on line 132
This is on line 132: if ($result->num_rows > 0) {
</div>