Cant create MySQL-Connection - Stuck at compiling - c++

Question

i worked for 4 years on Java. Now im trying to learn C++. I want to create a Teamspeak3-Plugin.
First of all i tried to create a MySQL-Connection and i stuck on compiling.
I worked with the MySQL-Connector for C++ Version 8.0.20 and Boost for C++(for the connector) Version 1.72.0
It gives me the ErrorCode "C3867" which is saying "non standard syntax use & to create a pointer to member"
I dont know why i am getting this error and especially how to solve it.
Here are my classes:
mysql.h:
#ifndef mysql_H
#define mysql_H
#include <iostream>
#include <string>
#include <mysql_connection.h>
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
using namespace std;
class mysql
{
public:
mysql();
int connect;
void createTables();
list<char*> getResult(char* qry);
};
#endif // !mysql_H
mysql.cpp
#include <iostream>
#include <string>
#include <mysql_connection.h>
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include "mysql.h"
using namespace std;
using namespace sql;
std::string host = "";
std::string port = "";
char* user = "";
char* password = "";
char* database = "";
sql::Driver *driver;
sql::Connection *con;
sql::ResultSet *res;
int connect() {
try {
driver = get_driver_instance();
std::string url = "tcp://" + host + ":" + port;
con = driver->connect(url, user, password);
cout << "MySQL connected!";
con->setSchema(database);
cout << "Database selected!";
return 0;
}
catch (sql::SQLException err) {
cout << "ERROR: " << err.what << endl;
}
}
void createTables() {
sql::Statement *stmt;
try {
stmt = con->createStatement();
stmt->executeQuery("CREATE TABLE IF NOT EXISTS JellyTest(Name VARCHAR(100), COINS INT)");
cout << "TableCreating done";
}
catch (sql::SQLException err) {
cout << "ERROR: " << err.what << endl;
}
}
list<char*> getResult(char* qry) {
sql::Statement *stmt;
sql::ResultSet *res;
list<char*> result;
try {
stmt = con->createStatement();
res = stmt->executeQuery(qry);
while (res->next) {
result.assign(res->next);
}
return result;
}
catch (sql::SQLException err) {
cout << "ERROR: " << err.what << endl;
}
}
Thanks for helping and have a nice day.
(I hope you are able to understand this text 'cause im from Germany)