这篇文章主要讲解了“怎么使用PHP查询两个表并将其合并”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“怎么使用PHP查询两个表并将其合并”吧！
首先，我们需要创建两个表并在表中插入一些数据。假设一个表名为“orders”，另一个表名为“customers”。orders表包括订单数据，包括订单号、订单日期、订单客户等等。而customers表则是客户数据，包括客户姓名、客户地址、客户电话等等。为了展示如何查询这两个表，我们创建如下表结构：
orders表
| order_id | order_date | customer_id |
|---|---|---|
| 1 | 2021-01-01 | 1 |
| 2 | 2021-01-02 | 2 |
| 3 | 2021-01-03 | 1 |
| 4 | 2021-01-04 | 3 |
customers表
| customer_id | customer_name | customer_address | customer_phone |
|---|---|---|---|
| 1 | Alice | New York | 123-456-7890 |
| 2 | Bob | Los Angeles | 234-567-8901 |
| 3 | Charlie | Chicago | 345-678-9012 |
| 4 | David | Houston | 456-789-0123 |
接下来，我们将使用PHP查询这两个表，并将其合并成一个表，以便于我们对数据进行操作。以下是示例代码：
// Connect to database
$host = "localhost";
$user = "username";
$password = "password";
$database = "database";
$connect = mysqli_connect($host, $user, $password, $database);
// Query orders table
$query = "SELECT * FROM orders";
$result = mysqli_query($connect, $query);
// Query customers table
$query = "SELECT * FROM customers";
$result2 = mysqli_query($connect, $query);
// Merge two tables
$merged_array = array();
while ($row = mysqli_fetch_assoc($result)) {
$customer_id = $row['customer_id'];
$customer_query = "SELECT * FROM customers WHERE customer_id = $customer_id";
$customer_result = mysqli_query($connect, $customer_query);
$customer_row = mysqli_fetch_assoc($customer_result);
$merged_array[] = array_merge($row, $customer_row);
}
// Show merged table
echo "<table>";
echo "<tr><th>Order ID</th><th>Order Date</th><th>Customer Name</th><th>Customer Address</th><th>Customer Phone</th></tr>";
foreach ($merged_array as $row) {
echo "<tr>";
echo "<td>" . $row['order_id'] . "</td>";
echo "<td>" . $row['order_date'] . "</td>";
echo "<td>" . $row['customer_name'] . "</td>";
echo "<td>" . $row['customer_address'] . "</td>";
echo "<td>" . $row['customer_phone'] . "</td>";
echo "</tr>";
}
echo "</table>";在上面的代码中，首先连接到数据库，然后查询orders和customers表，将结果存储到$result和$result2变量中。接下来，我们使用while循环和array_merge函数将两个表合并。在每个循环中，我们首先从orders表中获取特定行的customer_id，然后查询customers表以获取该客户的详细信息。最后，我们将两个数组合并，并将其添加到$merged_array变量中。最后，我们使用foreach循环在HTML表格中显示合并的表。