Question

在c#中怎么用sql server根据两张表之间共同属性查找到相应的值

各位大神们，请帮我解决一下这个问题吧，我想在C#下用SQL让两张表Movie 和User连接并且查询对应的电影名称，但是一直都是返回null，麻烦大家帮我分析一下~具体代码如下： SqlCommand movie = new SqlCommand("select M_NAME from [Movie] m join [User] u on (m.M_ID=u.U_MOVIE) where u.U_Name='" + textBox1.Text + "'and u.U_Password='" + textBox2.Text + "'", conn); SqlDataReader m_name = movie.ExecuteReader(); while(m_name.Read()) { int k = 0; user.listBox1.Text = (String)m_name[k]; k++; }两张表的截图为：

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Answer 1

SqlCommand movie = new SqlCommand("select M_NAME from [Movie] m join [User] u on (m.M_ID=u.U_MOVIE) where u.U_Name='" + textBox1.Text + "'and u.U_Password='" + textBox2.Text + "'", conn);
user.listBox1.Text =movie.ExecuteScalar;

这样改试一下。

追问

还是不行哎，那样会报错

追答

SqlCommand movie = new SqlCommand("select M_NAME from [Movie] m join [User] u on (m.M_ID=u.U_MOVIE) where u.U_Name='" + textBox1.Text + "' and u.U_Password='" + textBox2.Text + "'", conn);
这样呢？

追问

依然为空值哎

Answer 2

联合查询 inner join

Answer 3

数据库建视图,直接通过视图查询

追问

我使用了视图查询，依然返回null

代码如下：

 SqlCommand movie = new SqlCommand("select M_NAME from [User_Movie] where U_Name='" + textBox1.Text + "'and U_Password='" + textBox2.Text + "'", conn);