SQL內部聯接的Linq等效語句和IN語句

Question

CREATE TABLE PersonTask
(
PersonId INT NOT NULL,
WeekId INT NOT NULL,
WeekDaysTaskId INT,
WeekEndTaskId INT
)
GO
CREATE TABLE Task
(
Id INT PRIMARY KEY,
[Description] VARCHAR(250) NOT NULL
)
GO
INSERT INTO Task(Id, [Description]) VALUES(1, 'Task-01')
INSERT INTO Task(Id, [Description]) VALUES(2, 'Task-02')
INSERT INTO Task(Id, [Description]) VALUES(3, 'Task-03')
GO
INSERT INTO PersonTask(PersonId, WeekId, WeekDaysTaskId, WeekEndTaskId) VALUES(1, 1, NULL, 1)
INSERT INTO PersonTask(PersonId, WeekId, WeekDaysTaskId, WeekEndTaskId) VALUES(1, 2, 2, NULL)
INSERT INTO PersonTask(PersonId, WeekId, WeekDaysTaskId, WeekEndTaskId) VALUES(1, 3, 3, 3)
GO

SELECT 
        PT.PersonId, 
        WeekId,
        'Not on Bench' as [Status]
    FROM PersonTask AS PT
    INNER JOIN Task AS T ON T.Id IN (PT.WeekDaysTaskId, PT.WeekEndTaskId)
    WHERE WeekId = 3/*Param-1*/ and PersonId = 1/*Param-2*/

我試圖寫一個等效於上述T-sql語句的linq查詢，但是徒勞。 有人可以幫助C＃Linq查詢來獲取上面的T-SQL語句。

Answer 1

必須類似（假設您有personTaskQueryable和taskQueryable）：

from pt in personTaskQueryable
from t in taskQueryable
where (t.Id == pt.WeekDaysTaskId || t.Id == pt.WeekEndTaskId)
    && pt.WeekId == 3 && pt.PersonId == 1
select new { pt.PersonId, pt.WeekId, Status = "Not on Bench" }

我沒有嘗試，因為我是直接在答案文本框中編碼的，但是Linq文檔說您不能使用“ join”運算符執行此類操作，因為它僅支持equijoins。

解決方案是首先構建笛卡爾乘積並從那里限制結果集。