mysql

Question

我有一个 table，其中包含学生姓名和当前日期和时间以及他们的状态，如下所示

John have 3 day absent

Jane have 2 day absent

我有这段代码，但它计算的不是特定用户的所有缺席所以我想只显示 John 缺席日和 jane 缺席日如果我 select 它在下拉菜单中

<?php
$sql = "SELECT student_name, count(status) as numberOfabsent FROM attendance WHERE status = 'Absent' GROUP BY student_name";
        $result = $db->prepare($sql);
        $result->execute();
        while ($row = $result->fetch()) 
        echo $row['numberOfabsent'];
 ?>

Answer 1

    <?php
             $sql = "SELECT *, count(status) as numberOfabsent FROM attendance WHERE status = 'Absent' GROUP BY student_name";
             $result = $db->prepare($sql);
             $result->execute();
             while ($row = $result->fetch()) {
             $numberOfabsent = $row['numberOfabsent'];
             $absdate = $row['timestamp'];
             echo "<tr><td><a href='" . $configs->getConfig('WEB_ROOT') . "admin/adminuseredit.php?usertoedit=" . $row['student_name'] . "'>" . $row['student_name'] . "</a></td>"
             . "<td><div class='shorten'><a href='" . $row['numberOfabsent'] . "'>" . $numberOfabsent  . " days</a></div></td><td>" . $absdate . "</td>"
             . "<td class='text-center'><div class='btn-group btn-group-xs'><a href='".$configs->getConfig('WEB_ROOT')."admin/adminuseredit.php?usertoedit=".$row['student_name']."' title='Edit' class='open_modal btn btn-default'><i class='fa fa-pencil'></i> View</a>";
             echo"</tr>";
             }
     ?>

mysql - 通过选择用户名来计算每个用户的状态

mysql - count status for each user by selecting their name

php

select

count