SQL Server：根据第二个表中的ID更新包含来自同一个表的值的表

Question

我有一个名为STOCK的表，我想要更新它，如下所示：

-------------------------
NUMBER           | UNITS
-------------------------
NA13ALPK1010     |  9
NA13ALANA1010    | 11
NA13ALPK1065     |  4
NA13ALANA106     |  5
ON0003    XS     |  1
AT3322    2      |  3

基于名为PKGINV的第二个表，如下所示：

----------------------------------------
PKGNUMBER        | BOARDNUMBER
----------------------------------------
NA13ALPK1010   | NA13ALANA1010
NA13ALPK1065   | NA13ALANA106

首先，我希望能够使用某种类型的联接进行SELECT，以便我可以UNITS显示STOCK PKGNUMBER和BOARDNUMBER在PKGINV中{1}}。

然后，我想UNITS使用STOCK PKGINV.PKGNUMBER = STOCK.NUMBER PKGINV.BOARDNUMBER UNITS更新STOCK {/ 1}}。

因此，在更新后，NA13ALPK1010将UNITS 11（来自UNITS的{​​{1}}）NA13ALANA1010将NA13ALPK1065 UNITS 1 {}} 5（来自UNITS的{​​{1}}）。

先谢谢你的帮助！

Answer 1

您的SELECT只需加入STOCK表两次：

SELECT 
PKGNUMBER_Stock.UNITS AS PKGNUMBER_UNITS
,BOARDNUMBER_Stock.UNITS AS BOARDNUMBER_UNITS
FROM 
PKGINV AS pkginv
JOIN STOCK AS PKGNUMBER_Stock ON PKGNUMBER_Stock.NUMBER = pkginv.PKGNUMBER
JOIN STOCK AS BOARDNUMBER_Stock ON BOARDNUMBER_Stock.NUMBER = pkginv.BOARDNUMBER

同样，UPDATE语句应该只匹配上面的连接集：

UPDATE PKGNUMBER_Stock
SET PKGNUMBER_Stock.UNITS = BOARDNUMBER_Stock.UNITS
FROM 
PKGINV AS pkginv
JOIN STOCK AS PKGNUMBER_Stock ON PKGNUMBER_Stock.NUMBER = pkginv.PKGNUMBER
JOIN STOCK AS BOARDNUMBER_Stock ON BOARDNUMBER_Stock.NUMBER = pkginv.BOARDNUMBER

Answer 2

您需要将Stock加入PKGINV两次：

Update s
set s.UNITS = s2.UNITS 
from STOCK s
join PKGINV p on s.NUMBER = p.PKGNUMBER
join STOCK s2 on p.BOARDNUMBER = s2.NUMBER