sql - 使用 Select 语句进行 SQL 更新

Question

我必须通过查询联系人表将联系人姓名添加到分配表中。

Contact桌子：

 ID     First_name     Last_Name
 -----------------------------------
 1234   John           Jones
 9876   Mary           Smith

Assignment桌子

 ContactID   Name
 -----------------
  1234
  9876

使用这个查询我得到

子查询返回超过 1 个值。

询问：

 update A  
 set Name = (select  distinct first_name + ' ' + last_name from contacts c join        Assignments A on c.id = A.contact_id where A.contact_id = c.id)
 from Assignments  A 
 join contacts c on c.id = A.contact_id
 where c.id = A.contact_id

我错过了什么？

Answer 1

JOIN他们直接，像这样：

UPDATE a
SET a.Name = c.first_name + ' ' + c.last_name
FROM Assignments a
INNER JOIN Contacts c  ON c.id = A.contact_id

Answer 2

尝试

Update A
Set A.name = c.First_name + ' ' + c.Last_name
From Assignment A JOIN Contacts C ON A.ContactID = C.ID

Answer 3

不需要子选择

UPDATE A  
   SET Name = c.first_name + ' ' + c.last_name
FROM Assignments  A 
JOIN contacts c 
   ON c.id = A.contact_id

Answer 4

试试这个

UPDATE a
SET a.Name = c.first_name + ' ' + c.last_name
FROM Assignments a
INNER JOIN Contacts c  ON c.id = A.contact_id