mysql中的类别显示一次

Question

我有一些数据在数据库中，它的输出与ORDER BY category，我想知道如何只显示一次类别？

$SQL = mysql_query("SELECT id,name,category FROM table ORDER BY category,id"); 

所以我的脚本遍历整个表并按类别名排序所有项目。

我希望能够以显示类别名称，一旦如此，则其余值可以落在该类别内

我现在有这样的事情

while($r = mysql_fetch_array($SQL){ 
    $name = $r['name']; 
    $category = $r['category']; 

    echo $category; //I want to be able to echo this once 
    echo $name; // this will be echoed many times depending on the category this falls into 
} 

Answer 1

$category = null; 
while($r = mysql_fetch_array($SQL){ 
    $name = $r['name']; 

    if ($category != $r['category']) { 
     $category = $r['category']; 

     echo $category; //I want to be able to echo this once 
    } 
    echo $name; // this will be echoed many times depending on the category this falls into 
} 

Answer 2

这样做：

$prev_category = ""; 
while($r = mysql_fetch_array($SQL){ 
    $name = $r['name']; 
    $category = $r['category']; 

    if($prev_category != $category) 
     echo $category; 
    echo $name; 
    $prev_category = $category; 
} 

因此，只有在更改后才会打印新类别