Mysqli to Array foreach在foreach内; 在foreach中使用另一个mysqli to array不能正确地从外部数组中读取值

问题描述：

Ok here is my set up of the outer loop.

$sql    ="SELECT * from tblStock";
$result =mysqli_query($conn, $sql);
while($row=mysqli_fetch_array($result, MYSQLI_ASSOC)) {
    $rows[]=$row;
}
foreach($rows as $ad) {

Then keeping the connection open Inside of this loop I have a part I need to read the image urls from a database.

$sql        ="SELECT url from Photos where itemId ='" . $ad['ItemID'] . "';";
    echo $sql;
    $imageresult=mysqli_query($conn, $sql);
    while($imagerow=mysqli_fetch_array($imageresult, MYSQLI_ASSOC)) {
        $imagerows[]=$imagerow;
    }

I empty the variables that would be used inside the new loop so they are clean for every new row.

$image1="";
$image2="";
$image3="";
$count =0;

Then I use this to get out up to 3 image urls.

foreach($imagerows as $value) {
        switch($count) {
            case 2:
                $image3=$value['url'];
                $count =$count+1;
                break;
            case 1:
                $image2=$value['url'];
                $count =$count+1;
                break;
            case 0:
                $image1=$value['url'];
                $count =$count+1;
                break;
        } 
    }

These values are later written to new line in a tab file within the $rows as $ad foreach I set up at the beginning.

What I am getting is this below where the inner foreach loop for the pictures is getting stuck on the first item in the stock table and not reading from the new $ad['ItemID'] on each iteration.

好的，这是我对外循环的设置。 p>

  $ sql =“SELECT * from tblStock”; 
 $ result = mysqli_query（$ conn，$ sql）; 
while（$ row = mysqli_fetch_array（$ result，MYSQLI_ASSOC））{
 $ rows [] = $ row;  
} 
 
Nacach（$行为$ ad）{
  code>  pre> 
 
 然后保持连接打开在此循环的内部我有一个部分我需要读取图像网址 来自数据库。   p> 
 
 
  $ sql =“从照片中选择url，其中itemId ='”。  $ ad ['ItemID']。  “';”; 
 echo $ sql; 
 $ imageresult = mysqli_query（$ conn，$ sql）; 
 while（$ imagerow = mysqli_fetch_array（$ imageresult，MYSQLI_ASSOC））{
 $ imagerows [] = $ imagerow  ; 
} 
  code>  pre> 
 
 我清空将在新循环中使用的变量，以便它们对于每个新行都是干净的。 p> 
 
  
  $ image1 =“”; 
 $ image2 =“”; 
 $ image3 =“”; 
 $ count = 0; 
  code>  pre> 
 
 然后我使用它来获取最多3个图像网址。 p> 
 
   foreach（$ imagerows as $ value）{
 switch（$ count）{
 case 2  ：
 $ image3 = $ value ['url']; 
 $ count = $ count + 1; 
 break; 
 case 1：
 $ image2 = $ value ['url']; 
 $ count  = $ count + 1; 
 break; 
 case 0：
 $ image1 = $ value ['url']; 
 $ count = $ count + 1; 
 break; 
} 
} 
   code>  pre> 
 
 这些值稍后会在$行中的标签文件中写入新行，因为$ ad foreach I 在开始时设置。   p> 
 
 
我得到的是下面的内容，图片的内部foreach循环卡在了库存表的第一项而不是从新的$ ad ['ItemID']中读取 每次迭代。 p> 
 
 
    p> 
  div>

答

In your below code:

$sql ="SELECT url from Photos where itemId ='" . $ad['ItemID'] . "';"; echo $sql; $imageresult=mysqli_query($conn, $sql); while($imagerow=mysqli_fetch_array($imageresult, MYSQLI_ASSOC)) { $imagerows[]=$imagerow; }

You should reset the $imagerows[] array just before the while loop begins. So it should look like:

$sql ="SELECT url from Photos where itemId ='" . $ad['ItemID'] . "';"; echo $sql; $imageresult=mysqli_query($conn, $sql); $imagerows = array(); while($imagerow=mysqli_fetch_array($imageresult, MYSQLI_ASSOC)) { $imagerows[]=$imagerow; }

If you don't do that, everytime the results will keep getting added at the end of the $imagerows. Thus it will hold all elements of the entire result set. As a result, everytime it goes in foreach($imagerows as $value) loop, it will take the first 3 rows, assign their images & then not do anything (as you have restricted $count only for cases 0, 1 & 2.

Mysqli to Array foreach在foreach内; 在foreach中使用另一个mysqli to array不能正确地从外部数组中读取值

相关推荐