用連接更新表？

Question

我想更新從表B. 數據表A，我想我可以做這樣的事情

update A 
set A.DISCOUNT = 3 
from INVOICE_ITEMS A 
join ITEM_PRICE_QUNTITY B on A.ITEM_PRICE_NO = B.ID 
where A.INVOICE_ID = 33 

，但得到的錯誤 SQL消息：-104 無效令牌

誰能幫助我？

Answer 1

這是不可能用JOIN做到這一點。火鳥UPDATE聲明沒有FROM條款。該syntax是：

UPDATE {tablename | viewname} [[AS] alias] 
    SET col = newval [, col = newval ...] 
    [WHERE {search-conditions | CURRENT OF cursorname}] 
    [PLAN plan_items] 
    [ORDER BY sort_items] 
    [ROWS <m> [TO <n>]] 
    [RETURNING <values>] 

<m>, <n>  ::= Any expression evaluating to an integer. 
<values>  ::= value_expression [, value_expression ...] 
<variables> ::= :varname [, :varname ...] 

但是你的例子查詢相對應的是：

update INVOICE_ITEMS 
set DISCOUNT = 3 
WHERE EXISTS (SELECT 1 FROM ITEM_PRICE_QUNTITY B WHERE B.ID = ITEM_PRICE_NO) 
AND INVOICE_ID = 33 

如果你想利用附加的表中的數據進行更新，你可能要考慮使用MERGE。在你的評論索要相當於查詢做火鳥如下：

UPDATE B 
SET B.QUANTIY = b.QUANTIY + a.QUANTITY 
FROM ITEM_PRICE_QUNTITY B JOIN INVOICE_ITEMS A ON A.ITEM_PRICE_NO = B.ID 
WHERE A.INVOICE_ID = 33 

等效MERGE聲明將是：

MERGE INTO ITEM_PRICE_QUNTITY AS B 
    USING INVOICE_ITEMS AS A 
    ON A.ITEM_PRICE_NO = B.ID AND A.INVOICE_ID = 33 
    WHEN MATCHED THEN 
     UPDATE SET B.QUANTIY = B.QUANTIY + A.QUANTITY 

Answer 2

你可以使用這樣的：

update INVOICE_ITEMS 
set DISCOUNT = 3 
from (select * from ITEM_PRICE_QUNTITY) b 
where INVOICE_ITEMS.ITEM_PRICE_NO = B.ID and 
INVOICE_ITEMS.INVOICE_ID = 33