SQL引擎:MSSQL 目标:合并两个不同的总和 这是我的查询: 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
这里是交易,我有这样的SQL查询 SELECT *
FROM Customers AS C, Orders AS O, Orderlines AS OL
WHERE C.CustomerID = O.CustomerID AND O .OrderID = OL.OrderID
这关系代数是 Σ(C.CustomerID=O.CustomerID AND O.OrderID=OL.Order
如何创建一个类似于itertools.product()生成的Python生成器,但是它会遍历重复值列表?它会表现这样的嵌套循环for: theSet = 'ABC'
thePowers = range(4)
for i in thePowers:
for j in itertools.product(theSet, repeat=i):
print j
,但我想这
我有以下数据库: paperid | authorid | name
---------+----------+---------------
1889374 | 897449 | D. N. Page
1889374 | 1795881 | C. N. Pope
1889374 | 1952069 | S. W. Hawking
我想创建具有下列的表: paperid 作者姓名 -