How to make a request from PHP to the MySQL database?

The PDO class is used to work with the database in PHP.

DB connection

To connect to MySQL, you need to write such code (taken from here ),

 $host = '127.0.0.1'; $db = 'test'; $user = 'root'; $pass = ''; $charset = 'utf8mb4'; $options = [ PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, PDO::ATTR_EMULATE_PREPARES => false, ]; $dsn = "mysql:host=$host;dbname=$db;charset=$charset"; try { $pdo = new PDO($dsn, $user, $pass, $options); } catch (\PDOException $e) { throw new \PDOException($e->getMessage(), (int)$e->getCode()); } 

enter your own values ​​for the connection parameters and place in the db.php file.

After that in your script write include 'db.php'; and after that, the $pdo variable will be available in it, which will be used for all database queries.

Request execution

Performing a SELECT query involves 3 stages:

• preparation of the request, with question marks being put in place of all variables. This creates the $ stmt variable.
• execution of the request, in which all the variables involved in the request are sent separately, as an array, to the $stmt->execute() method.
• getting the requested data. Data can be obtained in three different ways.
  • single line as array or object, $stmt->fetch()
  • an array of strings, if the query can return more than one string, $stmt->fetchAll() . After that, the resulting array can be displayed via foreach() .
  • the only value is if we request a single column of a single row, $stmt->fetchColumn()
  • in very rare cases, the acquisition can be performed in a fourth way - sampling one line at a time in the loop, but we will not consider it here.

This is a scheme for performing any queries in which variables are involved. In this case, the code will be as follows:

 include 'db.php'; $stmt = $pdo->prepare('SELECT money FROM bot WHERE user_id=?'); // подготовка $stmt->execute([$id]); // выполнение $money = $stmt->fetchColumn(); // получение 

 $query = 'SELECT * FROM `bot` WHERE `user_id` = "'.mysqli_real_escape_string($mysqli, $id).'"'; 

The $ mysqli variable is your database connection, if you use a database connection, as in the example:

 $mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db'); 

But you, as a novice programmer, it is advisable to immediately use the connection to the database only through PDO - this is a safer option. In this case, the query syntax in $ query will have to be slightly edited.

Please edit your question as I wrote in the comments, and then the Stackoverflow community will have more chances to help you.