[英]Converted sql query to linq but not getting any result
我是Linq和Entity Framework的新手。
以下是我的工作存储过程,其中包括一个用逗号分隔的字符串( SUBSTRING
子句)
SELECT DISTINCT
SR.StudentRequestId,
SR.RegistrationId,
SR.Location,
SR.PaymentMethod,
SR.CreatedOn,
C.ClassName,
CC.CampusName,
CASE WHEN ISNULL(TSR.StatusId,0)=0 THEN 1 ELSE TSR.StatusId END AS StatusId,
SUBSTRING(
(SELECT', ' + REPLACE(REPLACE(ST1.FromTime,'AM',''),'PM','') + '-'+ ST1.ToTime AS [text()]
FROM dbo.StudentRequestTimings ST1
WHERE ST1.StudentRequestId = SRT.StudentRequestId
ORDER BY ST1.CreatedOn FOR XML PATH ('')
), 2, 1000) [Time] FROM StudentRequest SR
INNER JOIN Registration R ON R.RegistrationId = SR.RegistrationId
INNER JOIN Campus CC ON CC.CampusId = R.CampusId
INNER JOIN Class C ON C.ClassId = SR.ClassId
LEFT JOIN TutorClasses TC ON SR.ClassId = TC.ClassId
LEFT JOIN StudentRequestTimings SRT ON SR.StudentRequestId = SRT.StudentRequestId
LEFT JOIN TutorStudentRequest TSR ON TSR.StudentRequestId = SRT.StudentRequestId AND TutorId = @RegistrationId
WHERE TC.RegistrationId = @RegistrationId
ORDER BY SR.CreatedOn DESC
我需要在接受IQueryable<T>
的PagedList方法中使用此数据,并且我想将此SP转换为返回IQueryable
的LINQ查询(内部PagedList
方法使用.Skip()
和.Skip()
.Take()
执行服务器端分页)。
以下是我到目前为止的尝试,但是我不知道为什么我无法像从SQL查询中那样获得预期的结果。 我认为下面的代码有些错误。 谁能在下面的代码中找出问题所在?
var model = (from sr in db.StudentRequests
join r in db.Registrations on sr.RegistrationId equals r.RegistrationId
join cc in db.Campus on r.CampusId equals cc.CampusId
join c in db.Classes on sr.ClassId equals c.ClassId
from tc in db.TutorClasses.Where(t => t.ClassId == sr.ClassId).DefaultIfEmpty()
from srt in db.StudentRequestTimings.Where(s => s.StudentRequestId == sr.StudentRequestId).DefaultIfEmpty()
from tsr in db.TutorStudentRequests.Where(t => t.StudentRequestId == srt.StudentRequestId && t.TutorId == registrationid).DefaultIfEmpty()
where tc.RegistrationId == registrationid
select new TutorDashboard
{
StudentRequestId = sr.StudentRequestId,
RegistrationId = sr.RegistrationId,
Location = sr.Location,
PaymentMethod = sr.PaymentMethod,
CreatedOn = sr.CreatedOn,
ClassName = c.ClassName,
CampusName = cc.CampusName,
Time = string.Join(",", db.StudentRequestTimings.Where(p => p.StudentRequestId == sr.StudentRequestId).Select(p => p.FromTime.ToString().Replace("AM", "").Replace("PM", "") + "-" + p.ToTime.ToString())),
}).Distinct();
有人可以帮我解决为什么我无法从上述linq查询中得到正确的结果吗?
问题是在将以下代码添加到Linq时,我遇到了问题,如何解决此问题?
Time = string.Join(",", db.StudentRequestTimings.Where(p => p.StudentRequestId == sr.StudentRequestId).Select(p => p.FromTime.ToString().Replace("AM", "").Replace("PM", "") + "-" + p.ToTime.ToString())),
我添加此代码是因为我想从多行中获取一个字符串
1:00-1:30 PM, 2:00=2:30 PM
5:00-5:30 PM
像明智的
由于转换逗号分隔的代码时出现问题,我在下面的代码中实现了
var query = (from sr in db.StudentRequests
join r in db.Registrations on sr.RegistrationId equals r.RegistrationId
join cc in db.Campus on r.CampusId equals cc.CampusId
join c in db.Classes on sr.ClassId equals c.ClassId
from tc in db.TutorClasses.Where(t => t.ClassId == sr.ClassId).DefaultIfEmpty()
from srt in db.StudentRequestTimings.Where(s => s.StudentRequestId == sr.StudentRequestId).DefaultIfEmpty()
from tsr in db.TutorStudentRequests.Where(t => t.StudentRequestId == srt.StudentRequestId && t.TutorId == registrationid).DefaultIfEmpty()
where tc.RegistrationId == registrationid
select new
{
StudentRequestId = sr.StudentRequestId,
RegistrationId = sr.RegistrationId,
Location = sr.Location,
PaymentMethod = sr.PaymentMethod,
CreatedOn = sr.CreatedOn,
ClassName = c.ClassName,
CampusName = cc.CampusName,
StatusId = tsr.StatusId == null ? 1 : tsr.StatusId,
Time = db.StudentRequestTimings.Where(p => p.StudentRequestId == sr.StudentRequestId).Select(p => p.FromTime.ToString().Replace("AM", "").Replace("PM", "") + "-" + p.ToTime)
}).ToList().GroupBy(p => new { p.StudentRequestId }).Select(g => g.First()).ToList();
var model = query.AsEnumerable().Select(x => new TutorDashboard
{
StudentRequestId = x.StudentRequestId,
RegistrationId = x.RegistrationId,
Location = x.Location,
PaymentMethod = x.PaymentMethod,
CreatedOn = x.CreatedOn,
ClassName = x.ClassName,
CampusName = x.CampusName,
StatusId = x.StatusId == null ? 1 : x.StatusId,
Time = string.Join(",", x.Time),
}).ToList().ToPagedList(page ?? 1, 1);
可能对于某些需要用逗号分隔值并带有多个左连接的人来说,这段代码会有所帮助
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