Question

我尝试在VB.NET中的SQL Server 2012数据库上运行左连接，但我仍然坚持使用这段代码：

Dim dtTabelle1 as DataTable
(first Column of dtTabelle1 = Zyklus ID)

Dim con As SqlConnection
Dim conString, cmdString As String
Dim cmd As SqlClient.SqlCommand

conString = "path"
con = New SqlConnection(conString)
con.Open()

dtTabelle1.TableName = "Test"

cmdString = "INSERT INTO Daten ([Zyklus ID])" & _
                "Select [Zyklus ID]" & _
                "FROM Test " & _
                "LEFT JOIN Daten ON (Test.[Zyklus ID] = Daten.[Zyklus ID])" & _
                    "WHERE (Daten.[Zyklus ID] IS NULL);"

cmd = New SqlCommand(cmdString, con)
cmd.CommandType = CommandType.Text

cmd.ExecuteNonQuery()
con.Close()

我收到错误：

无效的对象名称＆＃39;测试＆＃39;

（顺便说一句，我无法更改＆＃34; Zyklus ID＆＃34; :(）中的空白。

dtTabelle1已填充且架构与服务器Daten上的目标数据库相同。

Answer 1

如果您使用别名表格

会更好

试试这样：

cmdString = "INSERT INTO Daten ([Zyklus ID])" & _
                "Select T.[Zyklus ID]" & _
                "FROM Test T " & _
                "LEFT JOIN Daten D ON (T.[Zyklus ID] = D.[Zyklus ID])" & _
                    "WHERE (D.[Zyklus ID] IS NULL);"

Answer 2

请在查询的SQL语句之间放置适当的空格

cmdString = "INSERT INTO Daten ([Zyklus ID]) " & _
            "SELECT [Zyklus ID] " & _
            "FROM Test " & _
            "LEFT JOIN Daten ON (Test.[Zyklus ID] = Daten.[Zyklus ID]) " & _
            "WHERE (Daten.[Zyklus ID] IS NULL);"

无法比较SQL和数据表并将新条目复制到sql表

2 个答案: