[英]How do I turn this into LINQ?
如何将我的SQL转换为LINQ?
DECLARE @cookie nvarchar(50)
SET @cookie = 'test@test.com'
SELECT s.firstname
FROM [examManager].[dbo].[students] AS s
JOIN [examManager].[dbo].tutors t ON s.last_exam IN (t.default_exam_id ,
t.last_exam, t.next_exam)
OR s.next_exam IN (t.default_exam_id , t.last_exam , t.next_exam)
--WHERE t.email = @cookie
我沿着这条路线走(在查询下),但是与SQL结果进行比较时,它并没有带回我需要的东西。 我将在C#中处理cookie,这不是问题。
var tStudents = from s in student
join t in tutor on s.last_exam equals t.default_exam_id //{ ColA = s.last_exam, ColB = s.next_exam } equals new { ColA = t.last_exam, ColB = t.next_exam }
join t2 in tutor on s.last_exam equals t2.last_exam
join t3 in tutor on s.last_exam equals t3.next_exam
//where t.email == finalCookie
select new
{
s.firstname,
s.lastname,
};
+++编辑+++为了使以上工作正常,请考虑以下两个示例表。
导师
------------------------------------------------------------
id |email | |default_exam_id| |last_exam|next_exam
------------------------------------------------------------
0 |test@test.com |903 |910 |903
------------------------------------------------------------
学生们
------------------------------------------------------------
id |fname | |last_exam |next_exam
------------------------------------------------------------
0 |john |903 |910
1 |doe |912 |903
2 |gary com |909 |988
------------------------------------------------------------
结果应该如下:
0 |john |903 |910
1 |doe |912 |903
这甚至是您想要的东西附近吗? 根据您在OP的评论中的描述,我已尽力而为。
List<string> students =
studentList.Where(
s =>
tutorList.Any(
t =>
t.last_exam == s.last_exam || t.next_exam == s.last_exam ||
t.default_exam_id == s.last_exam || t.last_exam == s.next_exam ||
t.next_exam == s.next_exam || t.default_exam_id == s.next_exam))
.Select(n => n.firstname + " " + n.lastname)
.ToList();
扩展我的评论:
我认为从语义上将条件放在where子句中也更正确。
var tStudents = from s in student
from t in tutor
where (s.last_exam == t.default_exam_id || s.last_exam == t.last_exam || s.last_exam == t.next_exam
|| s.next_exam == t.default_exam_id || s.next_exam == t.last_exam || s.next_exam == t.next_exam)
//&& t.email == finalCookie
select new
{
s.firstname,
s.lastname,
};
更新:
var result = tStudents.Distinct();
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