SELECT查询具有多个表的多列

本文介绍了SELECT查询具有多个表的多列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我附上一张我的问题的图片:

I attach one image of my problem:

在测试jFrame jTextField中，我将插入客户ID，然后按ok按钮后查询将选择并收集与该客户有关的信息.然后它将显示在jTableModel中.

我附上我的数据库图像.

错误是无法执行SQL代码".

推荐答案

您需要正确地连接表. 像这样:

You need to join the tables properly. Like this:

SELECT paper_list,monday,tuesday,wednesday,thrsday,friday,saturday,sunday,magzine_name,rate FROM papers LEFT JOIN papers_rate ON papers_rate.paperId = papers.id LEFT JOIN magzines ON magzines.paperId = papers.id LEFT JOIN magzines_rate ON magzines_rate.magazineId = magzines.id WHERE customer_id = ?"

如果您进行内部联接，例如，如果您没有magazine_rate，那么所有结果都将消失...

If you do an inner join, all your results will vanish if you don't have a magazine_rate for example...

并检查您的拼写. 您是在写 thrsday 而不是星期四，并写 magzine 而不是杂志...

And check your spelling. You're writing thrsday instead of thursday and magzine instead of magazine...

PS:customer_id来自哪里?

PS: And where does customer_id come from ?