php - MySQL 中的 FROM 子句无法指定更新目标表

Question

我想通过选择 requisition_id(其中 status 与特定关键字匹配)来更改单个订单的 status。 但它一直向我显示此错误“您无法在 FROM 子句中指定要更新的目标表”

UPDATE order_info
SET status ='Approved' 
WHERE requisition_no IN (SELECT requisition_no FROM order_info WHERE status = 'not approved')

我可以做什么来修复它？

编辑 - 我也包含了 PHP 代码

while ($row = mysqli_fetch_array($result)){
echo "<tr>";
    echo "<td>" . $row['requisition_no'] . "</td>";
    echo "<td>" . $row['desig'] . "</td>";
    echo "<td>" . $row['deptt'] . "</td>";
    echo "<td>" . $row['type'] . "</td>";
    echo "<td>" . $row['make'] . "</td>";
    echo "<td>" . $row['quantity'] . "</td>";
    echo '<form method="post" action="status.php">'; /*Redirects to status.php to change the status (using diff. page because i'm a hopeless kid, who doesnt want to learn new ways of simplifying things)*/
    echo "<td>" . $row['status'] . "<br/>";

    if($row['status']=='Approved' || $row['status']=='Under Procurement'){//does nothing
    }
            /*Here, using a submit button*/
    else { echo '<input type="submit" name="status" value="Approve"></td>';
    $_SESSION['rno'] = $row['requisition_no'];}
    echo '</form>';

Answer 1

您有一些语法错误可能导致此错误。您缺少 status 后面的等号 = 以及末尾的右括号 ):

UPDATE order_info o
SET o.status = 'Approved' 
WHERE o.requisition_no IN (SELECT x.requisition_no FROM (select * from order_info) x WHERE x.status = 'not approved')

另外，我认为您的查询可以这样重写:

UPDATE order_info
SET status = 'Approved' 
WHERE status = 'not approved'