The mysqli_fetch_assoc() function in PHP is used to fetch a result row as an associative array from a result set obtained using a MySQLi query.

🔹 Syntax:

mysqli_fetch_assoc(mysqli_result $result): array|null

• $result: The result object from a mysqli_query() call.
• Returns: An associative array of strings representing the fetched row, where column names are the keys, or NULL if there are no more rows.

🔹 Key Features:

• Only returns associative arrays (i.e., no numeric keys).
• Used commonly in while loops to fetch multiple rows.

🔹 Example 1: Basic usage

<?php
$conn = mysqli_connect("localhost", "root", "", "test_db");

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

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

mysqli_close($conn);
?>

Output (example):

ID: 1
Name: John
Email: john@example.com

ID: 2
Name: Alice
Email: alice@example.com

🔹 Example 2: Using fetched data in an array

<?php
$users = [];
$result = mysqli_query($conn, "SELECT * FROM users");

while ($row = mysqli_fetch_assoc($result)) {
    $users[] = $row;  // Store each row in $users array
}
print_r($users);
?>

Output (structure):

Array (
  [0] => Array ( [id] => 1 [name] => John [email] => john@example.com )
  [1] => Array ( [id] => 2 [name] => Alice [email] => alice@example.com )
)

✅ When to Use mysqli_fetch_assoc():

• When you only need column names as keys, without numeric indexes.
• In while loops to iterate through rows.
• When building APIs or JSON responses.