Using mysqli_fetch_assoc to Retrieve Query Results in PHP

In PHP, database operations are a core part of development, and the mysqli extension is a common way to work with MySQL. This article explains how to use the mysqli_fetch_assoc function to obtain query results.

1. Connect to the Database

First, use mysqli_connect to establish a connection to a MySQL server. Below is a sample code snippet:

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

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

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

2. Query the Database

Next, execute an SQL statement with mysqli_query. Example:

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

After running the query, fetch each row using mysqli_fetch_assoc, which returns the row as an associative array. Loop until no rows remain:

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

3. Full Example

The following complete script combines connection, query execution, result fetching, and cleanup:

$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"] . "<br>";
    }
} else {
    echo "0 结果";
}

mysqli_close($conn);

Note that the database name, credentials, and table structure should be adjusted to match your actual environment.

Summary

This article introduced how to use mysqli_fetch_assoc to retrieve query results: connecting to the database, executing a SELECT statement, and iterating over the result set with an associative array, enabling efficient backend data handling in PHP.