Linq根據日期之間的聯接表

Question

CREATE Table A
(StartDate DATETIME, 
EndDate DATETIME,
Price float)

CREATE Table B
(EfectiveDate DATETIME,
Item VARCHAR(50))

INSERT INTO A values ('01/20/2016', '11/12/2017', '2.40')
INSERT INTO A values ('11/13/2017', '03/02/2019', '1.20')
INSERT INTO A values ('03/03/2019', '05/22/2019', '2.20')
INSERT INTO A values ('05/23/2019', '07/23/2019', '1.90')

INSERT INTO B values ('06/21/2019' 'Pen')
INSERT INTO B values ('01/01/2018','Pencil')

我需要將這兩個表結合起來，根據表B中的生效日期，LINQ應該在表A中的StartDate和EndDate之間

就像是 ...

Select * FROM B
INNER JOIN A on B.EfectiveDate BETWEEN A.StartDate AND A.EndDate

要么

from tblB in B 
join tblA in A on tblB.B.EfectiveDate BETWEEN tblA.StartDate AND tblA.EndDate

顯然我上面的LINQ查詢是錯誤的，但我希望你明白這個想法。

Answer 1

你不能專門加入BETWEEN條件

你可以嘗試使用笛卡爾積，然后在適當的條件下過濾：

from tblB in B
from tblA in A
where tblB.EfectiveDate >= tblA.StartDate && tblB.EfectiveDate <=  tblA.EndDate
select new {
    StartDate = tblA.StartDate,
    EndDate = tblA.EndDate,
    Price = tblA.Price,
    EfectiveDate = tblB.EfectiveDate,
    Item = tblB.Item
};