查询在phpMyAdmin中有效，但在php中无效

Question

If I run the following code I get an error saying

"Warning: mysqli_error() expects exactly 1 parameter, 0 given in /home/u913241783/public_html/meeting_new.php on line 13"

which is the line with the query that starts $r1d . However if I run the query in phpMyAdmin it works fine.

I've tried splitting the two queries into separate <? ?> <? ?> as suggested on another question but it still did not work.

 <?php
    session_start();
    $input2 = $_SESSION[ 'unitid' ];

    include 'connect_db.php'; 

    $q1c="INSERT into meetings (unitid) VALUES ('$input2')";
    $r1c = mysqli_query($dbc,$q1c);

    $q1d = "SELECT max(meetingid) as newmeeting FROM meetings LIMIT 1)";
    $r1d = mysqli_query ($dbc, $q1d);
    while($row1d = mysqli_fetch_assoc($r1d))

    {
    echo" header ('location:editmeeting.php?id=" . $row1d['newmeeting'] .  ")";
    } 

Answer 1

I'm guessing that meetingid has no value.

Trapping on an error as suggested will not always work. If the query syntax is valid then no error is triggered, but you get no results.

Add an echo to your code:

$q1d = "SELECT max(meetingid) as newmeeting FROM meetings LIMIT 1)";
$r1d = mysqli_query ($dbc, $q1d);
echo mysqli_error() . "<br/>$q1d";

Then if necessary copy and paste the echoed query into the SQL query box in phpMyAdmin.