如何使4表内连接工作（VB.NET） [英] How do I get a 4 table inner join to work (VB.NET)

问题描述

截至目前，我可以使用内部联接获得3个表进行合并，但我似乎无法找到一种方法来将4+表内部连接起来。



这是我的代码：

As of right now I can get 3 tables to merge using an inner join, but I can not seem to find a way to get 4+ tables inner joined.

Here is my code:

Dim sqlcon As New SqlConnection("sqlstring")
     Dim sqladapt As New SqlDataAdapter("Select * From profile inner join (cemeteries inner join cemetery_reference on cemeteries.Cemetery_ID = cemetery_reference.Cemetery_ID)  on Profile.Individual_ID = Cemeteries.Individual_ID", sqlcon)

     sqlcon.Open()
     sqladapt.SelectCommand.ExecuteNonQuery()

     Dim DT As New DataTable
     sqladapt.Fill(DT)
     DataGridView1.DataSource = DT
     sqlcon.Close()

我一直收到语法错误



我尝试了什么：



我从单词之后尝试过双括号，但是，我仍然得到相同的语法错误。

I keep getting "incorrect syntax on"

What I have tried:

I have tried double parenthesis after the word from, however, I am still getting the same syntax error.

推荐答案

您没有提供有关DBMS的信息。然而......

在单个查询中可以加入的表的数量取决于DBMS ...



典型查询看起来例如：

You didn't provide information about DBMS. Nevertheless...
The number of tables available to join within single query depends on DBMS...

A "typical" query looks like:

SELECT A.<List_Of_Fields>, B.<List_Of_Fields>, C.<List_Of_Fields>, D.<List_Of_Fields>
FROM Table1 AS A
    INNER JOIN Table2 AS B ON A.PrimaryKey = B.ForeignKey
    INNER JOIN Table3 AS C ON B.PrimaryKey = C.ForeignKey
    INNER JOIN Table4 AS D ON C.PrimaryKey = D.ForeignKey

几种类型的连接。请参阅： SQL连接的可视化表示 [ ^ ]



详情请见：

MS SQL Server：查询加入 [ ^ ]

MS Access：加入表和查询 - 访问 [ ^ ]

There's few types of joins. See: Visual Representation of SQL Joins[^]

For further details, please see:
MS SQL Server: Querying with Joins[^]
MS Access: Join tables and queries - Access[^]

您应该在SqlManagement中尝试SQL，以便更快地进行SQL调试！ ;）

无论如何，我立即发现一个bu（可能还有更多......）



选择*来自个人资料内部联接（公墓内部联接...

应该是，而不是

选择*来自个人资料内部加入（从墓地内连接中选择* ...

you should try your SQL in SqlManagement, for faster SQL debugging! ;)
At any rate I immediatelyu spoted one bu (there might be more ...)

Select * From profile inner join (cemeteries inner join ...
should be, instead
Select * From profile inner join (select * from cemeteries inner join ...

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