选择SQL查询仅返回tableModel中数组的一个值

Question

我正在尝试从数据库的特定categories表中获取具有相似类别名称的商品行，并且，对于每一行，我都进行了第二次SQL查询以求和orders table过去一周的时间。我希望将结果添加到表模型中，但仅添加一行。

private void analyticsTableQuery(String Category) {
    this.categorySelected = Category;
    categoryTitle.setText(Category);
   int ordered;
    int initial;
    String query2 = "SELECT * FROM stock INNER JOIN category ON stock.Category_id=category.id where category.Category_Name='"+Category+"'";
    try {
            con = DriverManager.getConnection("jdbc:mysql://194.5.156.94:3306/u843360242_tukule?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC","u843360242_tukule","cocaine");
            pst = con.prepareStatement(query2);
            rs=pst.executeQuery();
            DefaultTableModel tm=(DefaultTableModel)analyticsTable.getModel();
            tm.setRowCount(0);
         while(rs.next()){
                int id = rs.getInt("stock.id");
                int current = rs.getInt("stock.Quantity");
                String name = rs.getString("stock.Name");
                String price = rs.getString("stock.Price");
                String query = "SELECT sum(Quantity) as 'sum' FROM `orders` WHERE Created_at >= DATE(CURRENT_DATE() -7) 
                and Stock_id ="+id; 
                try {
               con = DriverManager.getConnection("jdbc:mysql://localhost:3306/u843360242_tukule 
         useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC","root","");
               pst = con.prepareStatement(query);
               rs=pst.executeQuery();
               rs.next();
                   if(rs.getInt("sum") > 0)
                {
                  ordered = rs.getInt("sum");
                  initial = current + ordered;
                }
                else{ 
                  ordered = 0;
                  initial = current + ordered;
                }
                   Object o[]={
                            name,
                            price,
                            initial};
                   tm.addRow(o); 
               } catch (SQLException ex) {
                   Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
               }     
           }             
     } catch (SQLException ex) {
        Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
     }  
}   

Answer 1

您正在将结果集rs用于外部和内部结果。用内部结果集重新初始化rs会影响您的外部循环条件。而且即使rs中仍然存在行，由于正在进行循环，读取id, quantity, name等列也会导致异常，因为新结果集rs中可能不存在这些列。