我认为这是一个简单的例子，可能有人会更容易理解，

        DECLARE @TB1 TABLE
        (
            No Int
            ,Name NVarchar(50)
        )

        DECLARE @TB2 TABLE
        (
            No Int
            ,Name NVarchar(50)
        )

        INSERT INTO @TB1 VALUES(1,'asdf');
        INSERT INTO @TB1 VALUES(2,'awerq');


        INSERT INTO @TB2 VALUES(1,';oiup');
        INSERT INTO @TB2 VALUES(2,'lkjhj');

        SELECT * FROM @TB1

        UPDATE @TB1 SET Name =S.Name
        FROM @TB1 T
        INNER JOIN @TB2 S
                ON S.No = T.No

        SELECT * FROM @TB1

为未来的开发人员提供的一般答案。

SQL Server

UPDATE 
     t1
SET 
     t1.column = t2.column
FROM 
     Table1 t1 
     INNER JOIN Table2 t2 
     ON t1.id = t2.id;

Oracle(和SQL Server)

UPDATE 
     t1
SET 
     t1.colmun = t2.column 
FROM 
     Table1 t1, 
     Table2 t2 
WHERE 
     t1.ID = t2.ID;

MySQL

UPDATE 
     Table1 t1, 
     Table2 t2
SET 
     t1.column = t2.column 
WHERE
     t1.ID = t2.ID;

总结其他答案，关于如何仅在“匹配存在”时使用来自另一个表的数据更新目标表，有4种变体

查询和子查询:

update si
set    si.AccountNumber = (
    select ran.AccountNumber 
    from   RetrieveAccountNumber ran
    where  si.LeadID = ran.LeadID
)
from Sales_Import si
where exists (select * from RetrieveAccountNumber ran where ran.LeadID = si.LeadID)

内连接:

update si
set si.AccountNumber = ran.AccountNumber
from Sales_Import si inner join RetrieveAccountNumber ran on si.LeadID = ran.LeadID

交叉连接:

update si
set si.AccountNumber = ran.AccountNumber
from Sales_Import si, RetrieveAccountNumber ran
where si.LeadID = ran.LeadID

走：

merge into Sales_Import si
using RetrieveAccountNumber ran on si.LeadID = ran.LeadID 
when matched then update set si.accountnumber = ran.accountnumber;

所有的变体都是更少的琐碎和可以理解的，我个人更喜欢“内部连接”选项。但其中任何一种都可以使用，开发者必须根据自己的需求选择“更好的选项”

从性能的角度来看，使用join的变体更可取:

我想再补充一点。

不要用相同的值更新一个值，这会产生额外的日志记录和不必要的开销。 参见下面的例子-尽管链接了3条记录，但它只会在2条记录上执行更新。

DROP TABLE #TMP1
DROP TABLE #TMP2
CREATE TABLE #TMP1(LeadID Int,AccountNumber NVarchar(50))
CREATE TABLE #TMP2(LeadID Int,AccountNumber NVarchar(50))

INSERT INTO #TMP1 VALUES
(147,'5807811235')
,(150,'5807811326')
,(185,'7006100100007267039');

INSERT INTO #TMP2 VALUES
(147,'7006100100007266957')
,(150,'7006100100007267039')
,(185,'7006100100007267039');

UPDATE A
SET A.AccountNumber = B.AccountNumber
FROM
    #TMP1 A 
        INNER JOIN #TMP2 B
        ON
        A.LeadID = B.LeadID
WHERE
    A.AccountNumber <> B.AccountNumber  --DON'T OVERWRITE A VALUE WITH THE SAME VALUE

SELECT * FROM #TMP1

如果以上答案不适合你，试试这个

Update Sales_Import A left join RetrieveAccountNumber B on A.LeadID = B.LeadID
Set A.AccountNumber = B.AccountNumber
where A.LeadID = B.LeadID 

下面是在SQL Server中对我有效的方法:

UPDATE [AspNetUsers] SET

[AspNetUsers].[OrganizationId] = [UserProfile].[OrganizationId],
[AspNetUsers].[Name] = [UserProfile].[Name]

FROM [AspNetUsers], [UserProfile]
WHERE [AspNetUsers].[Id] = [UserProfile].[Id];