hat is the LINQ equivalent for the following SQL query? - sql

Question

T-SQL query:
SELECT T1.ID,
T1.UserId,
T1.ServerId,
T1.DiskId,
T1.Date_ PreviousDate_,
T1.Row,
MIN(T2.Date_) AS Date_,
DATEDIFF(MINUTE, T1.Date_, MIN(T2.Date_)) AS MinutesDiff
FROM IesLogs T1
LEFT JOIN IesLogs T2
ON T1.DiskId = T2.DiskId
where T1.DiskId = 2 AND T2.Date_ > T1.Date_ AND T1.Row = T2.Row
GROUP BY T1.ID,T1.UserId, T1.ServerId, T1.DiskId, T1.Date_, T1.[Row]
ORDER BY T1.DiskId, T1.[Row], T1.Id
I am getting more data than I expected.
var result = (
from i in context.IesLogs
join i2 in context.IesLogs
on i.DiskId equals diskId into i2left
from i3 in i2left.DefaultIfEmpty()
where
i.UserId == userId
&& i3.Date > i.Date
&& i.Row == i3.Row
group i3 by new {i.Id, i.ServerId,i.DiskId, i.Row, PreviousDate = i.Date, i3.Date} into logs
orderby logs.Key.DiskId, logs.Key.Row,logs.Key.Id ascending
select new IesLogStatisticsDto
{
Id = logs.Key.Id,
ServerId = logs.Key.ServerId,
DiskId = logs.Key.DiskId,
PreviousDate = logs.Key.PreviousDate,
Date = logs.Min(x => x.Date),
Row = logs.Key.Row,
DateDiff = Convert.ToInt32((logs.Min(x => x.Date) - logs.Key.PreviousDate).TotalMinutes)
}).ToList();
I'm getting 12 when I should be getting 6 data. How Can I solve this ?
I think the reason why I'm getting a lot of data is the(i3.Date > i.Date) in the code blog above but I have to implement this line.

Answer 1

Your LINQ query has wrong grouping. You have to remove i3.Date from grouping key.
A little bit refactored:
var query =
from i in context.IesLogs
join i2 in context.IesLogs
on i.DiskId equals diskId into i2left
from i2 in i2left.DefaultIfEmpty()
where
i.UserId == userId
&& i2.Date > i.Date
&& i.Row == i2.Row
group i2 by new {i.Id, i.ServerId, i.DiskId, i.Row, PreviousDate = i.Date} into logs
orderby logs.Key.DiskId, logs.Key.Row, logs.Key.Id ascending
select new IesLogStatisticsDto
{
Id = logs.Key.Id,
ServerId = logs.Key.ServerId,
DiskId = logs.Key.DiskId,
PreviousDate = logs.Key.PreviousDate,
Date = logs.Min(x => x.Date),
Row = logs.Key.Row,
DateDiff = Convert.ToInt32((logs.Min(x => x.Date) - logs.Key.PreviousDate).TotalMinutes)
};