SQL - 未选择数据库

Question

我正在使用预准备语句从数据库返回项目，但是当我执行它时，会抛出没有数据库选择错误。

public void getTheMarketData() throws SQLException, ClassNotFoundException{
    Connection con = DBConnection.getConnection();
    Logger log = Logger.getLogger(Login.class.getName());
    PreparedStatement returnMarketData = con.prepareStatement
    ("SELECT  dealer_table.Dealer_Name, standard_dealer_link.*, standards_table.Standard_Value"
    + "FROM project.standard_dealer_link"
    + "inner join dealer_table on standard_dealer_link.DealerID = dealer_table.DealerID"
    + "inner join standards_table on standard_dealer_link.StandardID = standards_table.StandardID"
    + "where standard_dealer_link.Quarter= " + this.Quarter
    + "and dealer_table.Market = '" + this.Market + "';");
    ResultSet marketRS = returnMarketData.executeQuery();

有什么东西真的很简单吗？这种确切的格式适用于我的其他陈述。