Question

使用LEFT JOIN连接两个MSSQL数据库（在同一台服务器上）时遇到了很大的问题。我从数据库OLAB_DB运行此SQL并获取错误：

The multi-part identifier "OLAP_DB.dbo.OLAP_invoice.UserID" could not be bound.

DB似乎无法找到自己的问题，我不知道如何解决这个问题。我有两次和三次检查拼写并重写SQL几次，但现在我只需要放弃并寻求帮助：（

这不起作用：

SELECT TOP 200 
    COALESCE(LTRIM(RTRIM(contact_db.dbo.ContactTable.EmailAdr)),LTRIM(RTRIM(contact_db.dbo.CustomerTable.EmailAdr))) AS EMAIL,
    OLAP_invoice.OrdreLinjeID AS ORDERNO
    OLAP_invoice.SalgsPris AS PRICE,
    OLAP_invoice.UserID AS CONTACTID
FROM OLAP_invoice,contact_db.dbo.CustomerTable
    LEFT JOIN contact_db.dbo.ContactTable 
    ON OLAP_DB.dbo.OLAP_invoice.UserID = contact_db.dbo.ContactTable.UserID
WHERE contact_db.dbo.CustomerTable.ClientID = OLAP_invoice.ClientID

但跳过左连接只是从两个不同的数据库中获取数据就可以了。

这很好用：

SELECT TOP 200 
    LTRIM(RTRIM(contact_db.dbo.CustomerTable.EmailAdr)) AS EMAIL,
    LTRIM(RTRIM(contact_db.dbo.ContactTable.UserID)) AS EMAIL2,
    OLAP_invoice.OrdreLinjeID AS ORDERNO
    OLAP_invoice.SalgsPris AS PRICE,
    OLAP_invoice.UserID AS CONTACTID
FROM OLAP_invoice,contact_db.dbo.CustomerTable
WHERE contact_db.dbo.CustomerTable.ClientID = OLAP_invoice.ClientID
AND contact_db.dbo.ContactTable.UserID = OLAP_invoice.UserID

我需要LEFT JOIN的原因是因为某些订单未使用UserID（仅ClientID）注册。我已经检查了访问权限，单独访问字段没有问题，当我必须比较LEFT JOIN中的值并指定绝对路径时会出现问题。

你知道什么是错的吗？

Answer 1

你可以试试这个：

SELECT TOP 200   COALESCE(LTRIM(RTRIM(contact_db.dbo.ContactTable.EmailAdr)),LTRIM(RTRIM(contact_db.dbo.CustomerTable.EmailAdr))) AS EMAIL,
        OLAP_invoice.OrdreLinjeID AS ORDERNO
        OLAP_invoice.SalgsPris AS PRICE,
        OLAP_invoice.UserID AS CONTACTID
FROM OLAP_invoice LEFT JOIN contact_db.dbo.ContactTable ON OLAP_DB.dbo.OLAP_invoice.UserID = contact_db.dbo.ContactTable.UserID, contact_db.dbo.CustomerTable
WHERE contact_db.dbo.CustomerTable.ClientID = OLAP_invoice.ClientID

Answer 2

您从OLAP_invoice中选择，但加入OLAP_DB.dbo.OLAP_invoice。您需要每次都使表格完全相同，或使用别名。所以：

FROM OLAP_DB.dbo.OLAP_invoice
left join contact_db.dbo.ContactTable
on OLAP_DB.dbo.OLAP_invoice...

OR

FROM ROM OLAP_invoice
LEFT JOIN ontact_db.dbo.ContactTable
ON OLAP_invoice...

或者您也可以使用别名，而不是那样打字。

FROM OLAP_invoice OI
LEFT JOIN ontact_db.dbo.ContactTable CT
ON OI...

Answer 3

就个人而言，我试图避免在FROM中有多个表，而没有故意指定联接的类型。

我觉得这样的东西更具可读性和可维护性：

SELECT TOP 200 
    COALESCE( LTRIM(RTRIM(con.EmailAdr)), LTRIM(RTRIM(cus.EmailAdr)) ) AS EMAIL,
    i.OrdreLinjeID AS ORDERNO
    i.SalgsPris AS PRICE,
    i.UserID AS CONTACTID

FROM OLAP_invoice i
    LEFT JOIN contact_db.dbo.CustomerTable cus ON cus.ClientID = i.ClientID
    LEFT JOIN contact_db.dbo.ContactTable con ON con.UserID = i.UserID

左连接两个数据库时出错（SQL Server）

3 个答案: