PHP database operation skills: How to use the mysqli_fetch_assoc function to obtain query results

PHP database operation skills: How to use the mysqli_fetch_assoc function to obtain query results

In PHP, database operations are a very important part of development. Using the mysqli extension library for database operations is one of the common methods. This article will introduce how to use the mysqli_fetch_assoc function to obtain query results.

1. Connect to the database
   First, we need to use the mysqli_connect function to establish a connection with the MySQL database. The following is a sample code:

$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";

$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检查连接是否成功
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

2. Query database
   Next, we can use the mysqli_query function to execute SQL query statements. The following is a query example:

$sql = "SELECT id, name, email FROM users";
$result = mysqli_query($conn, $sql);

After executing the query, we can use the mysqli_fetch_assoc function to get the results of each row, returned in the form of an associative array. Each call to this function will return the next row of data until all rows of data have been fetched.

while ($row = mysqli_fetch_assoc($result)) {
    echo "ID: " . $row["id"] . ", Name: " . $row["name"] . ", Email: " . $row["email"] . "
";
}

3. Complete example
   The following is a complete example showing how to use the mysqli_fetch_assoc function to obtain query results:

$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";

$conn = mysqli_connect($servername, $username, $password, $dbname);

if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

$sql = "SELECT id, name, email FROM users";
$result = mysqli_query($conn, $sql);

if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_assoc($result)) {
        echo "ID: " . $row["id"] . ", Name: " . $row["name"] . ", Email: " . $row["email"] . "
";
    }
} else {
    echo "0 结果";
}

mysqli_close($conn);

It should be noted that the database and database in this example The table structure needs to be replaced according to the actual situation.

Summary:
This article introduces how to use the mysqli_fetch_assoc function to obtain query results. We can easily obtain data from the database by connecting to the database, executing query statements, and traversing the result set using the mysqli_fetch_assoc function. By properly using the mysqli_fetch_assoc function, we can operate the database more efficiently and improve development efficiency.

I hope this article can be of some help to PHP database operations. thanks for reading!

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