sql查询中的笛卡尔积 - c＃ [英] cartesian product in sql query - c#

问题描述

大家好。



我在C＃中遇到sql查询问题:(。



这里是代码：

Hello guys.

I have a problem with the sql query in C# :(.

here is the code:

dts.Tables.Clear();
           
SqlDataAdapter da = new SqlDataAdapter("SELECT t.Date, t.Barcode, t.Name, t.Quantity, d.BuyPrice, t.SellPrice FROM tblSales t, tblMagazine d WHERE t.Date BETWEEN '" + DateTimePicker1.Value + "' AND '" + DateTimePicker2.Value + "'", con);

da.Fill(dts);

dataGridView1.DataSource = dts.Tables[0];

它给了我笛卡尔积或类似的东西....因为当我点击按钮（有这个代码）它向我展示了比表Sales中更多的表格。



有什么问题？有人可以帮我吗

It gives me cartesian product or something like that.... because when I click the button (that has this code) it shows me more tables than I have in the table Sales.

What is the problem ?? Can someone help me

推荐答案

tblSales 和 tblMagazine 没有共同点...你对笛卡儿是正确的;



销售与杂志之间的联系是什么，因为这个缺失。

tblSales and tblMagazine don''t have something in common... you''re right about the cartesian;

What''s the link between Sales and Magazine, due this one''s missing.

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