The first method uses a foreach loop

$arr = [    
    [
        'name' => 'testname1',
        'age' => 18,
    ],
    [
        'name' => 'testname2',
        'age' => 19,
    ],
    [
        'name' => 'testname3',
        'age' => 18,
    ],
];

$servername = "localhost";
$port = 3306;
$username = "username";
$password = "password";
$dbname = "mytestdb";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname, $port);

// Detection connection
if ($conn->connect_error) {
 die("connect failed: " . $conn->connect_error);
} 

$costBegin = microtime(true);

foreach($arr as $item) {
    $sql = sprintf("INSERT INTO user_info (name, age) VALUES ( '%s', %d);", $item['name'], (int)$item['age']);   
    if ($conn->query($sql) === TRUE) {
     echo "insert success";
    } else {
     echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

$costEnd = microtime(true);
$cost = round($costEnd - $costBegin, 3);
var_dump($cost);

$conn->close();

Compare inserting a small amount of data with inserting a large amount of data, using the for loop above to insert time-consuming:

The second uses insert to merge inserts

In mysql, insert statements can be used to merge and insert, such as
INSERT INTO user_info (name, age) VALUES ('name 1', 18), ('name 2', 19); indicates insertion of two data at a time

$arr = [    
    [
        'name' => 'testname1',
        'age' => 18,
    ],
    [
        'name' => 'testname2',
        'age' => 19,
    ],
    [
        'name' => 'testname3',
        'age' => 18,
    ],
    // Omit here
    ......
    ......
];

$servername = "localhost";
$port = 3306;
$username = "username";
$password = "password";
$dbname = "mytestdb";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname, $port);

// Detection connection
if ($conn->connect_error) {
 die("connect failed: " . $conn->connect_error);
} 

$costBegin = microtime(true);

if (!empty($arr)) {
    $sql = sprintf("INSERT INTO user_info (name, age) VALUES ");

    foreach($arr as $item) {
  $itemStr = '( ';
  $itemStr .= sprintf("'%s', %d", $item['name'], (int)$item['age']);
  $itemStr .= '),';
  $sql .= $itemStr;
  }

 // Remove the last comma and add the closing semicolon
 $sql = rtrim($sql, ',');
 $sql .= ';';

    if ($conn->query($sql) === TRUE) {
    } else {
     echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

$costEnd = microtime(true);
$cost = round($costEnd - $costBegin, 3);
var_dump($cost);

$conn->close();

Let's take a look at the time comparison between a small amount of data and a large amount of data. From the overall time, we can see that insert merge insert saves a lot of time than for loop insert just now. The effect is obvious.