SQL Server触发器使用链接表更新行

Question

我正在使用SQL Server。 我有三个表， Contacts ， Companies和Links 。

插入Contact ，我想用相应Company信息更新列。 有一个Link表，其中的ToID与ContactID相对应，而FromID与CompanyID相对应。

这是我要使用的查询，但是我对SQL不够熟悉，无法使其正常工作。

CREATE TRIGGER dbo.Contacts.AddressFromCompany
ON dbo.Contacts
AFTER INSERT AS
BEGIN
    SET NOCOUNT ON

    IF inserted.Address1 IS NULL AND 
       inserted.Address2 IS NULL AND 
       inserted.Address3 IS NULL AND 
       inserted.City IS NULL AND 
       inserted.State IS NULL AND 
       inserted.ZipCode IS NULL AND 
       inserted.Country IS NULL

        UPDATE cont 
        SET Address1 = comp.Address1,
            Address2 = comp.Address2,
            Address3 = comp.Address3,
            City     = comp.City,
            State    = comp.State,
            ZipCode  = comp.ZipCode,
            Country  = comp.Country
        FROM dbo.Companies comp
        WHERE 
            comp.CompanyID = dbo.Links.ToID 
            AND dbo.Links.FromID = inserted.ContactID;
 END

谢谢你的帮助！

凯尔

Answer 1

在创建联系人之前，不了解链接如何包含ContactId，但是此代码可以满足您的要求。 （假设ContactID是唯一的）。

UPDATE Contacts
SET Address1 = Companies.Address1
   ,Address2 = Companies.Address2
   ,Address3 = Companies.Address3
   ,City     = Companies.City
   ,State    = Companies.State
   ,ZipCode  = Companies.ZipCode
   ,Country  = Companies.Country
FROM Contacts
     INNER JOIN Links
        ON Links.FromID = Contacts.ContactsID
     INNER JOIN Companies
        ON Companies.CompanyID = Links.ToID
     INNER JOIN inserted
        ON inserted.ContactId = Contacts.ContactID
WHERE inserted.Address1 IS NULL 
      AND inserted.Address2 IS NULL 
      AND inserted.Address3 IS NULL 
      AND inserted.City IS NULL 
      AND inserted.State IS NULL 
      AND inserted.ZipCode IS NULL 
      AND inserted.Country IS NULL