我必须更新一个由3个表的连接返回的值的字段。
例子:
select
im.itemid
,im.sku as iSku
,gm.SKU as GSKU
,mm.ManufacturerId as ManuId
,mm.ManufacturerName
,im.mf_item_number
,mm.ManufacturerID
from
item_master im, group_master gm, Manufacturer_Master mm
where
im.mf_item_number like 'STA%'
and im.sku=gm.sku
and gm.ManufacturerID = mm.ManufacturerID
and gm.manufacturerID=34
我想更新表item_master的mf_item_number字段值，使用在上述条件中连接的其他一些值。
如何在MS SQL Server中做到这一点?
当前回答
将其应用到MySQL中——UPDATE中没有FROM子句，但这是可行的:
UPDATE
item_master im
JOIN
group_master gm ON im.sku=gm.sku
JOIN
Manufacturer_Master mm ON gm.ManufacturerID=mm.ManufacturerID
SET
im.mf_item_number = gm.SKU --etc
WHERE
im.mf_item_number like 'STA%'
AND
gm.manufacturerID=34
其他回答
试试这样……
Update t1.Column1 = value
from tbltemp as t1
inner join tblUser as t2 on t2.ID = t1.UserID
where t1.[column1]=value and t2.[Column1] = value;
UPDATE im
SET mf_item_number = gm.SKU --etc
FROM item_master im
JOIN group_master gm
ON im.sku = gm.sku
JOIN Manufacturer_Master mm
ON gm.ManufacturerID = mm.ManufacturerID
WHERE im.mf_item_number like 'STA%' AND
gm.manufacturerID = 34
为了说清楚…UPDATE子句可以引用FROM子句中指定的表别名。所以在这种情况下im是有效的
通用的例子
UPDATE A
SET foo = B.bar
FROM TableA A
JOIN TableB B
ON A.col1 = B.colx
WHERE ...
你可以用MERGE命令更新，对MATCHED和NOT MATCHED有更多的控制:(我稍微改变了源代码，以证明我的观点)
USE tempdb;
GO
IF(OBJECT_ID('target') > 0)DROP TABLE dbo.target
IF(OBJECT_ID('source') > 0)DROP TABLE dbo.source
CREATE TABLE dbo.Target
(
EmployeeID INT ,
EmployeeName VARCHAR(100) ,
CONSTRAINT Target_PK PRIMARY KEY ( EmployeeID )
);
CREATE TABLE dbo.Source
(
EmployeeID INT ,
EmployeeName VARCHAR(100) ,
CONSTRAINT Source_PK PRIMARY KEY ( EmployeeID )
);
GO
INSERT dbo.Target
( EmployeeID, EmployeeName )
VALUES ( 100, 'Mary' );
INSERT dbo.Target
( EmployeeID, EmployeeName )
VALUES ( 101, 'Sara' );
INSERT dbo.Target
( EmployeeID, EmployeeName )
VALUES ( 102, 'Stefano' );
GO
INSERT dbo.Source
( EmployeeID, EmployeeName )
VALUES ( 100, 'Bob' );
INSERT dbo.Source
( EmployeeID, EmployeeName )
VALUES ( 104, 'Steve' );
GO
SELECT * FROM dbo.Source
SELECT * FROM dbo.Target
MERGE Target AS T
USING Source AS S
ON ( T.EmployeeID = S.EmployeeID )
WHEN MATCHED THEN
UPDATE SET T.EmployeeName = S.EmployeeName + '[Updated]';
GO
SELECT '-------After Merge----------'
SELECT * FROM dbo.Source
SELECT * FROM dbo.Target
MySQL:一般来说，根据你的需求做必要的改变:
UPDATE
shopping_cart sc
LEFT JOIN
package pc ON sc. package_id = pc.id
SET
sc. amount = pc.amount
我一直在尝试做这样的事情，我刚刚想到尝试使用以下语法(使用元组)
update dstTable T
set (T.field1, T.field2, T.field3) =
(select S.value1, S.value2, S.value3
from srcTable S
where S.key = T.Key);
令人惊讶的是，它奏效了。我用的是甲骨文(我想是12c)。这是标准SQL或Oracle专用的吗?
注意:在我的例子中，我正在更新整个表(填充新列)。更新没有where子句，因此将更新所有行。当子查询不返回行时，字段将被设置为NULL。(并且它不能返回多于一行)。
