Oracle 11 g

merge into Sales_Import
using RetrieveAccountNumber
on (Sales_Import.LeadId = RetrieveAccountNumber.LeadId)
when matched then update set Sales_Import.AccountNumber = RetrieveAccountNumber.AccountNumber;

使用下面的查询块根据ID更新Table1和Table2:

UPDATE Sales_Import, RetrieveAccountNumber 
SET Sales_Import.AccountNumber = RetrieveAccountNumber.AccountNumber 
where Sales_Import.LeadID = RetrieveAccountNumber.LeadID;

这是解决这个问题最简单的方法。

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

甲骨文

use

UPDATE suppliers
SET supplier_name = (SELECT customers.customer_name
                     FROM customers
                     WHERE customers.customer_id = suppliers.supplier_id)
WHERE EXISTS (SELECT customers.customer_name
              FROM customers
              WHERE customers.customer_id = suppliers.supplier_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:

根据匹配的id从一个表更新到另一个表

UPDATE 
     TABLE1 t1, 
     TABLE2 t2
SET 
     t1.column_name = t2.column_name 
WHERE
     t1.id = t2.id;