SQL引擎:MSSQL 目標:合併兩個不同的總和 這是我的查詢: SELECT z.zlec_id AS zlec,
(
CASE WHEN Sum(netto_blind_discout * p.count) IS NOT NULL
THEN
Sum(netto_blind_discout * p.count)
ELSE
這裏是交易,我有這樣的SQL查詢 SELECT *
FROM Customers AS C, Orders AS O, Orderlines AS OL
WHERE C.CustomerID = O.CustomerID AND O .OrderID = OL.OrderID
這關係代數是 Σ(C.CustomerID=O.CustomerID AND O.OrderID=OL.Order
如何創建一個類似於itertools.product()生成的Python生成器,但是它會遍歷重複值列表?它會表現這樣的嵌套循環for: theSet = 'ABC'
thePowers = range(4)
for i in thePowers:
for j in itertools.product(theSet, repeat=i):
print j
,但我想這
我有以下數據庫: paperid | authorid | name
---------+----------+---------------
1889374 | 897449 | D. N. Page
1889374 | 1795881 | C. N. Pope
1889374 | 1952069 | S. W. Hawking
我想創建具有下列的表: paperid 作者姓名 -