SQL - 选择distinct [英] SQL - select distinct

问题描述

我使用select disctinct语句与我的sql数据库表中的2个字段。这是我的代码。

I used the select disctinct statement with 2 fields from my sql database table. Here is my code.

myCommand = New SqlCommand("SELECT DISTINCT Author FROM tblBook UNION SELECT DISTINCT BookCode FROM tblBook",myConnection)
 myAdapter = New SqlDataAdapter(myCommand)
 myAdapter.Fill(myDataSet, "tblBook")
 cboAuthor.DataSource = myDataSet.Tables(0)
 cboAuthor.DisplayMember = "Author"
 cboAuthor.DisplayValue = "BookCode"

，它会产生错误：无法绑定到新成员。参数名称：value 。请帮助

and it generates error : cannot bind to the new member. Parameter name:value. Please help

推荐答案

您在sql语句中只选择了一列，作者。
BookCode不存在，所以它不会在数据集中。

you have selected only one column in your sql statement, Author. BookCode isn't present so it won't be in the dataset either.

在Sql语句中包含BookCode，它将被修复

Include the BookCode in the Sql Statement and it will be fixed

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