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
上面没有使用sql，这里有一个基于连接语句更新表的例子。
UPDATE p
SET p.category = c.category
FROM products p
INNER JOIN prodductcatagories pg
ON p.productid = pg.productid
INNER JOIN categories c
ON pg.categoryid = c.cateogryid
WHERE c.categories LIKE 'whole%'
其他回答
你可以在update语句中使用"FROM "子句指定用于确定如何更新以及更新内容的其他表，如下所示:
update item_master
set mf_item_number = (some value)
from
group_master as gm
join Manufacturar_Master as mm ON ........
where
.... (your conditions here)
在WHERE子句中，需要提供将这些表绑定在一起的条件和连接操作。
Marc
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
您可以使用以下查询:
UPDATE im
SET mf_item_number = (some value)
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 `sql`
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 ...
上面没有使用sql，这里有一个基于连接语句更新表的例子。
UPDATE p
SET p.category = c.category
FROM products p
INNER JOIN prodductcatagories pg
ON p.productid = pg.productid
INNER JOIN categories c
ON pg.categoryid = c.cateogryid
WHERE c.categories LIKE 'whole%'
