php query MySQL result array

PHP is a popular server-side scripting language widely used for Internet application development. In web development, it is often necessary to query data from the MySQL database and display the query results on the web page. This article will introduce how to use PHP to query a MySQL database and store the query results into a PHP array.

1. Connecting to MySQL database

To connect to MySQL database in PHP, you need to use mysqli or PDO extension. The following is an example of using the mysqli extension to connect to a MySQL database:

$servername = "localhost"; // 数据库主机名
$username = "username"; // 数据库用户名
$password = "password"; // 数据库密码
$dbname = "myDB"; // 数据库名

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

In the above example, $servername, $username, $password and $dbname are the host name, user name, password and database name of the database respectively. During the process of creating a connection, if the connection fails, the code will execute the die() function and output an error message indicating that the connection failed.

2. Query MySQL database

After connecting to the MySQL database, you can use SQL statements to query the data in the database. The following is an example of querying the MySQL database and outputting the query results:

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出每行数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
} else {
    echo "0 结果";
}

In the above example, $sql is the query statement, and $result is the query result. If there is data in the query results, the code will enter a while loop, read the query results row by row, and store each row of data into the $row array. Programmers can use the key values ​​in the $row array to obtain the value of the corresponding field as needed, and process it accordingly.

3. Storing MySQL query results into a PHP array

In the above example, the query results are read row by row and stored in $row in the array. If you need to store the entire query results into a PHP array, you can use the following sample code:

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 存储查询结果
    $rows = array();
    while($row = $result->fetch_assoc()) {
        $rows[] = $row;
    }
    // 输出查询结果
    print_r($rows);
} else {
    echo "0 结果";
}

In the above example, the query results are stored into the $rows array, and use print_r() The function outputs the entire array. Programmers can process the entire query results accordingly as needed.

4. Disconnect the MySQL database connection

After completing the query operation of the MySQL database, you need to disconnect the database connection through the following code:

$conn->close();

In the above In the example, the programmer uses the close() method to disconnect the database and release database resources.

Summary:

This article introduces how to use PHP to query the MySQL database and store the query results in a PHP array. Studying the contents of this article can help programmers better query the MySQL database and process the query results when using PHP for web development. During the actual development process, programmers can further optimize the code according to specific business needs to achieve more efficient MySQL database query operations.

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