多次插入问题

Question

当我使用此代码时，我会为存储在 users 表中的每个 id 获得一条记录。相反，我希望每次只能插入 1 条记录，即与记录的用户 ID 匹配的记录。

if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// escape variables for security
$acname = mysqli_real_escape_string($con, $_POST['ACName']);
$btu = mysqli_real_escape_string($con, $_POST['BTU']);
$space = mysqli_real_escape_string($con, $_POST['Space']);
$energyclass = mysqli_real_escape_string($con, $_POST['EnergyClass']);



$sql="INSERT INTO aircondition (id, ACName, BTU, Space,  EnergyClass)
SELECT id, '$acname', '$btu', '$space', '$energyclass'
FROM  users";

if (!mysqli_query($con,$sql)) {
  die('Error: ' . mysqli_error($con));
}
header('location:aircondition.php');


mysqli_close($con);
?>

Answer 1

您的选择语句中必须有 where 子句

$sql="INSERT INTO aircondition (id, ACName, BTU, Space,  EnergyClass)
SELECT id, '$acname', '$btu', '$space', '$energyclass'
FROM  users WHERE usernamecolumn= currentusername ;