Php 如何一次从mysql输出两列值并循环tru其余部分

在使用mysql的php中，如何只输出两列值一次，然后循环其他列

在这里：

期望输出：

Category->SubCategory //Outputted only once

Title,  //Title Body and Views depend on whatever's there in the db. Could be 10 or more
Body,
Views

Title,
Body,
Views

Title,
Body,
Views

---

一种解决方案可能是一个bool，它可以记住类别是否已经输出：

$exe_fetch_data = mysql_query("select category, subcategory, title, body, views from table");
$category_output_done = false;
while($row = mysql_fetch_array($exe_fetch_data))
{
    if (!$category_output_done) {
        echo $row['category'];    //Only once
        echo $row['subcategory']; //Only once
        $category_output_done = true;
    }

    echo $row['title'];
    echo $row['body'];
    echo $row['views'];
}

另一种解决方案可以是每次迭代时递增的计数器。

添加一个简单的计数器-

$counter = 0;
$exe_fetch_data = mysql_query("select category, subcategory, title, body, views from table");
while($row = mysql_fetch_array($exe_fetch_data))
if ($counter == 0){
echo $row['category'];    //Only once
echo $row['subcategory']; //Only once
$counter = 1;
}

---

这段代码应该可以做到这一点

    $exe_fetch_data = mysql_query("select category, subcategory, title, body, views from table");
    $row_once = mysql_fetch_array($exe_fetch_data)
    echo $row_once['category'];    //Only once
    echo $row_once['subcategory']; //Only once

   while($row = mysql_fetch_array($exe_fetch_data)) {
    echo $row['title'];
    echo $row['body'];
    echo $row['views'];
    }

您还可以尝试使用一个标志，其值最初为true，在第一次迭代后将变为false。

---

但是我认为上面的代码会比使用标志更快，因为它不会在每次迭代后比较/检查标志值，并且有一个巨大的数据库，它会节省执行时间。

因为您可能会有很多结果，所以在while循环中保留一个标志，无论您是否显示了已经消耗CPU的类别。由于您总是使用第一个结果集显示类别，因此我不会在while循环中保留标志，而是这样做：

$exe_fetch_data = mysql_query("select category, subcategory, title, body, views from table");
$iNrOfResults = mysql_num_rows($exe_fetch_data);
//See if the result set has any rows at all, display the categories once
if(iNrOfResults > 0)
{
    $row = mysql_fetch_array($exe_fetch_data)
    echo $row['category'];    //Only once
    echo $row['subcategory']; //Only once
    echo $row['title'];
    echo $row['body'];
    echo $row['views'];
}

//See if there are any more results, do not display the categories anymore
if(iNrOfResults > 1)
{
    while($row = mysql_fetch_array($exe_fetch_data))
    {
        echo $row['title'];
        echo $row['body'];
        echo $row['views'];
    }
}

---

在第一次显示后，将标志添加到false out the loop，然后添加到true

$exe_fetch_data = mysql_query("select category, subcategory, title, body, views from table");
$iNrOfResults = mysql_num_rows($exe_fetch_data);
//See if the result set has any rows at all, display the categories once
if(iNrOfResults > 0)
{
    $row = mysql_fetch_array($exe_fetch_data)
    echo $row['category'];    //Only once
    echo $row['subcategory']; //Only once
    echo $row['title'];
    echo $row['body'];
    echo $row['views'];
}

//See if there are any more results, do not display the categories anymore
if(iNrOfResults > 1)
{
    while($row = mysql_fetch_array($exe_fetch_data))
    {
        echo $row['title'];
        echo $row['body'];
        echo $row['views'];
    }
}