Why is nothing displayed when querying the database if a search is made by value from "Russian" letters?

Question

MySQL

I make a query to the database on the name column, and if the name consists of English. letters, then everything is displayed. If name consists of Russian. letters, then nothing comes:

The first few lines from the database:

Request and output code:

ResultSet resultSetManufacturerID = DBHandler.executeQuery("SELECT ID FROM manufacturer WHERE Name = '"+ManufacturerTitle+"'");
                String manufacturerID = null;
                try {
                    while (resultSetManufacturerID.next()) {
                        manufacturerID = resultSetManufacturerID.getString(1);

                    }
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
System.out.println("manufacturerID: " + manufacturerID);

executeQuery code:

public static ResultSet executeQuery(String sql) {
        ResultSet resultSet = null;
        System.out.println(sql);
        try {
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            if (sql.contains("SELECT")) {
                resultSet = preparedStatement.executeQuery();

            } else {
                preparedStatement.executeUpdate();
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return resultSet;
    }

What could be the problem?
If I copy the request and paste it into the workbench, then everything works, the ID is displayed.

Answer 1

First, you should not use string concatenation to form sql queries. Secondly, you should make sure that the string encoding matches the database encoding.