使用其他查询循环MySQL结果

Question

我希望有人能够帮助我概念化我正在编写的PHP页面的解决方案。

实际上，我在一个名为“服务器”的MySQL数据库中有一个主表。 其中有四个字段； 部门 ， 服务器A ， 服务器B ， 服务器C。 对于上下文，部门条目是部门的名称，并且serverA，serverB和serverC对应于每个部门的三台服务器的主机名。

我正在尝试获取部门，服务器A，服务器B和服务器C的名称，然后使用该数据填充多个SQL查询。 我将数据分为多个表以保持整洁和相互关系。 这就是我所拥有的；

<?php
$conn = mysqli_connect("server", "root", "root") or die('Error connecting to MySQLserver.');
mysqli_select_db($conn, "Database") or die("Failed to connect to database");
$sql = "SELECT * FROM Servers";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
    $deptartment = $row['department']
    $serverA = $row['serverA'];
    $serverB = $row['serverB'];
    $serverC = $row['serverC'];
}
} else {
echo "Unable to connect to server.  Please check your settings.";
}
?>

, wherein record of serverA, the following happens; 然后，我想做的是一种 ，其中serverA的记录发生以下情况；

<?php
$conn = mysqli_connect("server", "root", "root") or die('Error connecting to MySQLserver.');
mysqli_select_db($conn, "Database") or die("Failed to connect to database");
$sql = "SELECT * FROM Data WHERE `serverName` = '$serverA' ORDER BY `timestamp` DESC LIMIT 1";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
    $serverName = $row['serverName'];
    $serverType = $row['serverType'];
    $serverAge = $row['serverAge'];
}
} else {
echo "Unable to connection to server.  Please check your settings.";
}
?>

然后，我可以使用相同的理论遍历serverB的结果，并让serverB的每个记录执行另一个查询以获取其他数据。

对于如何循环遍历每个结果并用它填充其他查询，我似乎在使用正确的语法。

有任何可能的指导吗？

谢谢！

Sample Data:
department: Math
serverA: math-server-windows.school.edu
serverB: math-server-mac.school.edu
serverC: math-server-linux.school.edu

department: Psychology
serverA: psychology-server-windows.school.edu
serverB: psychology-server-mac.school.edu
serverC: psychology-server-linux.school.edu

department:  Arts
serverA: artsserver.school.edu
serverB: artsold.school.edu
serverC: artsbackup.school.edu

Answer 1

您可以使用JOIN简化此过程。

表Data的字段servername对应于服务器表中的serverA ， serverB或serverC 。 因此，您可以运行如下查询：

SELECT Data.*,
  A.serverA AS serverA, 
  B.serverB AS serverB, 
  C.serverC AS serverC 
FROM Data
JOIN servers as A on Data.servername = A.serverA
JOIN servers as B on Data.servername = B.serverB
JOIN servers as C on Data.servername = C.serverC
ORDER BY <whatever>

因此，现在每一行都将包含每个部门的服务器信息，因此可以像这样遍历结果：

while( $row = $result->fetch_assoc() ){
  echo "\nDept: ".$row['department'];
  echo "\nA: ".$row['serverA'];
  echo "\nB: ".$row['serverB'];
  echo "\nC: ".$row['serverB'];
}