Can a prepared statement hold multiple queries in php - php

Question

I am trying to protect my queries from SQL injections, recently. I have started turning the strings I used to make the queries into statements, however, some of the strings I made need to make multiple queries simultaneously, because one insert's id will be added to the next one as a foreign key, which I'll get by using the LAST_INSERT_ID(), and I need them to be executed one after another because of it.
Can a statement hold multiple queries simultaneously and be executed at once?
Here's what the code was before, by the by.
$sql = "INSERT INTO `user_info`(`first_name`, `last_name`, `phone`, `cpf`)
VALUES ('{$firstName}', '{$lastName}', '{$phone}', '{$cpf}');";
$sql .= "SELECT LAST_INSERT_ID() INTO #mysql_variable_here;";
$sql .= "INSERT INTO `{$table}`(`email`, `password`, `active`,`user_info_id`, `created`, `role_id`" . $restaurantInsert . ")
VALUES ('{$email}','{$password}', 1, #mysql_variable_here, '{$created}', {$role}" . $restaurantValue . " );";
$sql .= "INSERT INTO `address`(number, street, city, state, zip, district, country, created, user_info_id)
VALUES ('{$number}', '{$street}', '{$city}', '{$stateCode}', '{$zip}', '{$district}', 'BR', '{$created}', #mysql_variable_here);";
$result = $conn->multi_query($sql);```

Answer 1

You can't execute multiple statements in a prepared query:
SQL syntax for prepared statements does not support multi-statements
(that is, multiple statements within a single string separated by ;
characters)
so you will need to prepare and execute each of the queries separately, using mysqli_stmt::insert_id to get the appropriate id value for the second and third queries:
$sql = "INSERT INTO `user_info`(`first_name`, `last_name`, `phone`, `cpf`)
VALUES (?, ?, ?, ?)";
$stmt = $conn->prepare($sql);
$stmt->bind_param('ssss', $firstName, $lastName, $phone, $cpf);
$stmt->execute();
$insert_id = $stmt->insert_id;
$stmt->close();
$sql = "INSERT INTO `{$table}`(`email`, `password`, `active`,`user_info_id`, `created`, `role_id`" . $restaurantInsert . ")
VALUES (?, ?, ?, ?, ?, ?, ?)";
$stmt = $conn->prepare($sql);
$stmt->bind_param('ssiisss', $email, $password, 1, $insert_id, $created, $role, $restaurantValue);
$stmt->execute();
$stmt->close();
$sql = "INSERT INTO `address`(number, street, city, state, zip, district, country, created, user_info_id)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?);";
$stmt = $conn->prepare($sql);
$country = 'BR';
$stmt->bind_param('sssssssi', $number, $street, $city, $stateCode, $zip, $district, $country, $created, $insert_id);
$stmt->execute();
$stmt->close();
Note I'm not 100% certain what you're trying to achieve with role_id" . $restaurantInsert . ", you might need to edit the second query appropriately to use that.