SQL腳本在phpAdmin中工作，但不在網站上回顯

Question

以下SQL腳本在phpMyAdmin的SQL編輯器中工作。但是，在PHP中我無法讓這個腳本在線顯示真實內容。這全是空白。這個問題在我的迴應中。我嘗試使用$row['a.qty']，但沒有奏效。

$sql = "SELECT a.qty + b.qty - c.qty as 'QTY', a.part_num as 'Part Num', a.part_desc as 'Description' 
     FROM Inv_Physical_Count a, 
       Inv_Restock b, 
       Inv_Orders c 
     WHERE a.part_id = b.part_id 
     AND  a.part_id = c.part_id 
     ORDER BY a.order_form_seq"; 

     $q = $pdo->prepare($sql); 
     $q->execute(array()); 

     while ($row = $q->fetch(PDO::FETCH_ASSOC)) 
     { 
      echo '<tr>'; 
      echo '<td>' . $row['qty'] . '</td>'; 
      echo '<td>' . $row['part_num'] . '</td>'; 
      echo '<td>' . $row['part_desc'] . '</td>';    
     } 

Answer 1

首先，反勾號（未報價）你AS值，特別是當它們包含空格：

$sql = "SELECT a.qty + b.qty - c.qty as `QTY`, a.part_num as `Part Num`, a.part_desc as `Description` 

你告訴查詢這些值應該是列名。正因爲如此使用AS值作爲數組標識符：

while ($row = $q->fetch(PDO::FETCH_ASSOC)) 
{ 
    echo '<tr>'; 
    echo '<td>' . $row['QTY'] . '</td>'; 
    echo '<td>' . $row['Part Num'] . '</td>'; 
    echo '<td>' . $row['Description'] . '</td>';    
}