javascript - 表内数据分组

Question

我有这样的代码

<table>
            <tr>
            <th> Subject </th>
            <th> Description </th>
            <th> Units </th>
            <th> Prerequisite Subject</th>
            </tr>
<?php
$dep = $_SESSION['course'];

$con = mysql_connect("localhost","root","");
        if(!$con){
        die('Could not connect to database' .mysql_error());
        }
        else{
        mysql_select_db("enrollment", $con);
        }       
        $result = mysql_query("SELECT * FROM tblsubject where department='$dep' order by year asc, semester asc ");
        if(!$result){
        die('Invalid query:' .mysql_error());
        }
        else{
        $cur_year= '';
        $cur_semester = '';
        while($row = mysql_fetch_array($result))
        {
        if($cur_year !== $row['year'] or $cur_semester !== $row['semester']){
        echo'<tr>';
        echo'<td colspan="7" align="center"><b>'.$row['year'].'</b></td>';
        echo'</tr>';
        echo'<tr>';
        echo'<td colspan="7" align="center"><b>'.$row['semester'].' Semester</b></td>';
        echo'</tr>';

        $cur_year = $row['year'];
        $cur_semester = $row['semester'];

        $sequel = "select sum(units) as sum_value from tblsubject where department='$dep' and year='$cur_year' and semester='$cur_semester' order by year asc, semester asc";
        $results = mysql_query($sequel);

        $cur_unit= '';

        while($rrr = mysql_fetch_assoc($results)){
        if($cur_unit!== $row['units']){
        echo'<tr>';
        echo'<td colspan="7" align="right"><b>Total Of : '.$rrr['sum_value'].' Units</b></td>';
        echo'</tr>'; 

        $cur_unit = $rrr['sum_value'];
        }
        } 
        }

        echo'<tr>';
        echo'<td>'.$row['sub_code'].'</td>';
        echo'<td>'.$row['sub_desc'].'</td>';
        echo'<td>'.$row['units'].'</td>';
        echo'<td>'.$row['prereq'].'</td>';
        echo'</tr>';

        }
        }

?>  
        </table>    

我有这样的输出。

| Subject | Description | Units | Prerequisite Subject|
|                   First Year                        |
|                First Semester                       |
|                 Total Units : 3 Units               |
|  IT111  | IT Major    |   3   |      none           |

我想将每学期的总学分放在所列科目的底部。

一定是这样的。

| Subject | Description | Units | Prerequisite Subject|
|                   First Year                        |
|                First Semester                       |
|  IT111  | IT Major    |   3   |      none           |
|                 Total Units : 3 Units               |

因为如果我将总单位代码放在下面来计算添加每个主题后将输出的总单位。

Answer 1

不推荐使用 mysql，您应该考虑使用 PDO 或 mysqli，它们都有返回行数的语句。 http://au1.php.net/manual/en/mysqli-stmt.num-rows.php对于 mysqli 和 http://au1.php.net/manual/en/pdostatement.rowcount.php对于 PDO。

如果您仍然想使用 MySQL，可以使用 mysql_num_rows。

一旦您了解了 PDO，您应该不会遇到任何问题。