MySQL是一款非常流行的關系型數據庫管理系統，它的使用十分廣泛，特別是在Web開發中。在進行MySQL操作時，我們需要使用一些代碼來實現我們的目標。下面是一些常見的MySQL操作代碼。

//連接數據庫    
$servername = "localhost";    
$username = "username";    
$password = "password";    
$dbname = "myDB";    
//創建連接    
$conn = new mysqli($servername, $username, $password, $dbname);    
//檢查連接    
if ($conn->connect_error) {    
die("Connection failed: " . $conn->connect_error);    
}    
//創建數據庫    
$sql = "CREATE DATABASE myDB";    
if ($conn->query($sql) === TRUE) {    
echo "Database created successfully";    
} else {    
echo "Error creating database: " . $conn->error;    
}    
//查詢數據    
$sql = "SELECT id, firstname, lastname FROM MyGuests";    
$result = $conn->query($sql);    
if ($result->num_rows >0) {    
// 輸出數據    
while($row = $result->fetch_assoc()) {    
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "
";    
}    
} else {    
echo "0 results";    
}    
//插入數據    
$sql = "INSERT INTO MyGuests (firstname, lastname, email) VALUES ('John', 'Doe', 'john@example.com')";    
if ($conn->query($sql) === TRUE) {    
echo "New record created successfully";    
} else {    
echo "Error: " . $sql . "
" . $conn->error;    
}    
//更新數據    
$sql = "UPDATE MyGuests SET lastname='Doe' WHERE id=2";    
if ($conn->query($sql) === TRUE) {    
echo "Record updated successfully";    
} else {    
echo "Error updating record: " . $conn->error;    
}    
//刪除數據    
$sql = "DELETE FROM MyGuests WHERE id=3";    
if ($conn->query($sql) === TRUE) {    
echo "Record deleted successfully";    
} else {    
echo "Error deleting record: " . $conn->error;    
}    
//關閉連接    
$conn->close();

以上是一些常見的MySQL操作代碼。這些代碼可以幫助開發者快速實現一些常用的數據庫操作。當然，數據庫操作需要謹慎處理，應避免出現數據丟失或者泄露的情況。