選擇產品從類別ID

Question

我想選擇我的不同類別表中的項目，但其只顯示了我。如果使用（），我試圖用ELSEIF

if($get_idy='Cars'){  
      $sel = mysqli_query($con,"SELECT * FROM item WHERE category='Cars' "); 
      }elseif($get_idy='Trucks'){ 
          $sel = mysqli_query($con,"SELECT * FROM item WHERE category='Trucks' "); 
          } 
      while($row= mysqli_fetch_array($sel)) 
      { 

有人能幫忙嗎？

Answer 1

如果條件存在於你的代碼中，你就會犯錯。單獨的「=」賦值給變量，雙「==」檢查變量的值是否相同。它應該如下所示。

if($get_idy=='Cars'){  
         $sel = mysqli_query($con,"SELECT * FROM item WHERE category='Cars' "); 
        } elseif($get_idy=='Trucks'){ 
         $sel = mysqli_query($con,"SELECT * FROM item WHERE category='Trucks' "); 
        } else{ 
         echo "The category is empty"; 
        } 
        while($row= mysqli_fetch_array($sel)) 
        { 
        } 

Answer 2

你可以做像每一個類別這不是檢查條件，

$sel = mysqli_query($con,"SELECT * FROM item WHERE category='".$get_idy."'"); 
while($row= mysqli_fetch_array($sel)) { 
    //Your code here. 
} 

請開始使用PDO爲您的SQL是容易受到SQL注入

更新：發佈基於此更新您的評論

if(isset($get_idy)) { 
    $sel = mysqli_query($con,"SELECT * FROM item WHERE category='".$get_idy."'"); 
    while($row= mysqli_fetch_array($sel)) { 
    //Your code here. 
} 
} else { 
    echo "The category is empty"; 
}