对于SQL Server 2008 +使用MERGE而不是专有的更新…FROM语法有一些吸引力。

它不仅是标准SQL，因此更易于移植，而且在源端有多个连接行的情况下(因此在更新中可能使用多个不同的值)也会引发错误，而不是最终结果不确定。

MERGE INTO Sales_Import
   USING RetrieveAccountNumber
      ON Sales_Import.LeadID = RetrieveAccountNumber.LeadID
WHEN MATCHED THEN
   UPDATE 
      SET AccountNumber = RetrieveAccountNumber.AccountNumber;

然而，不幸的是，选择使用哪一种可能并不完全取决于首选的风格。SQL Server中MERGE的实现一直受到各种错误的困扰。Aaron Bertrand在这里整理了一份报告的清单。

PostgreSQL的:

UPDATE Sales_Import SI
SET AccountNumber = RAN.AccountNumber
FROM RetrieveAccountNumber RAN
WHERE RAN.LeadID = SI.LeadID; 

我相信一个带JOIN的UPDATE FROM会有帮助:

MS SQL

UPDATE
    Sales_Import
SET
    Sales_Import.AccountNumber = RAN.AccountNumber
FROM
    Sales_Import SI
INNER JOIN
    RetrieveAccountNumber RAN
ON 
    SI.LeadID = RAN.LeadID;

MySQL和MariaDB

UPDATE
    Sales_Import SI,
    RetrieveAccountNumber RAN
SET
    SI.AccountNumber = RAN.AccountNumber
WHERE
    SI.LeadID = RAN.LeadID;

似乎你正在使用MSSQL，然后，如果我没记错，它是这样做的:

UPDATE [Sales_Lead].[dbo].[Sales_Import] SET [AccountNumber] = 
RetrieveAccountNumber.AccountNumber 
FROM RetrieveAccountNumber 
WHERE [Sales_Lead].[dbo].[Sales_Import].LeadID = RetrieveAccountNumber.LeadID

在同一个表内更新:

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

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

    INSERT INTO @TB1 VALUES(1,'changed person data',  0);
    INSERT INTO @TB1 VALUES(2,'old linked data of person', 1);

INSERT INTO @TB2 SELECT * FROM @TB1 WHERE linkNo = 0


SELECT * FROM @TB1
SELECT * FROM @TB2


    UPDATE @TB1 
        SET Name = T2.Name
    FROM        @TB1 T1
    INNER JOIN  @TB2 T2 ON T2.No = T1.linkNo

    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;