How to Use mysqli_fetch_assoc in PHP to Retrieve Query Results

In PHP, database operations are a crucial part of development. Using the mysqli extension is a common method. This article introduces how to use the mysqli_fetch_assoc function to obtain query results.

1. Connect to Database

First, we need to use the mysqli_connect function to establish a connection to a MySQL database. Below is an example code:

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

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

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

2. Query Database

Next, we can use the mysqli_query function to execute an SQL query.

Here is a query example:

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

After executing the query, we can use mysqli_fetch_assoc to fetch each row of the result as an associative array. The function returns the next row on each call until all rows are retrieved.

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

3. Full Example

Below is a complete example demonstrating how to use mysqli_fetch_assoc to fetch query results:

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

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

if (!$conn) {
    die("Connection failed: " . 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 results";
}

mysqli_close($conn);

Note: The database name, credentials, and table structure in the example should be replaced with those of your actual environment.

Summary

This article introduced how to use the mysqli_fetch_assoc function to retrieve query results. By connecting to the database, executing a query, and iterating the result set with mysqli_fetch_assoc, developers can easily access data and improve development efficiency.

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