从mysql数据库中回显数据

Question

hi everybody have a good day . i have an question regarding to echo value form mysql database Now i have a table name ---> materialachievement Inside the table i have 3 column (chapter ,subchapter and part)

the data is like below:

chapter      subchapter         part
-------------------------------------
2               2.1               1
2               2.1               2
2               2.1               3
2               2.2               1
2               2.2               2
3               3.1               1
3               3.1               1
-------------------------------------

Now i want do a table to echo chapter 2 and 3 and inside chapter 2 has subchapter 2.1 and subchapter 2.2 inside subchapter 2.1 has part 1 , 2 , 3 and inside subchapter 2.2 has part 1 , 2

the structure is like :

2
 2.1
    1
    2
    3
 2.2
    1
    2

So my question is how can i just echo chapter 2 for once , then subchapter 2.1 for once , then go to part 1 , 2 , 3 ? same with sunchapter 2.2.

$query="SELECT * FROM materialachievement WHERE sID=$id GROUP BY (chapter and subchapter) ORDER BY chapter ASC , subchapter ASC ";

$result=mysql_query($query,$conn);

if($result === FALSE) 
{
die(mysql_error()); // TODO: better error handling
}

while($row=mysql_fetch_array($result))
{
    $chapter = $row['chapter'];
    $subchapter = $row['subchapter'];

    echo "<br>Chapter :".$chapter."<br>";
    echo "<br>Subchapter :".$subchapter."<br>";
}

now the result suppose be : chapter 2 , subchapter 2.1 , subchapter 2.2 , subchapter 2.3 and chapter 3 , subchapter 3.1 , subchapter 3.2

Answer 1

$query="SELECT * FROM materialachievement WHERE sID=$id ORDER BY chapter ASC, subchapter ASC, part ASC ";

$result=mysql_query($query,$conn);

if($result === FALSE) 
{
die(mysql_error()); // TODO: better error handling
}

$last_chapter = null;
while($row=mysql_fetch_array($result))
{
    $chapter = $row['chapter'];
    $subchapter = $row['subchapter'];
    $part = $row['part'];
    if ($last_chapter !=== $chapter) {
        echo "Chapter: $chapter<br>";
        $last_chapter = $chapter;
        $last_subchapter = null;
    }
    if ($subchapter !== $last_subchapter) {
        echo "Subchapter: $subchapter<br>";
        $last_subchapter = $subchapter;
    }
    echo "Part: $part<br>";
}