LINQ语句中的多个OR子句

Question

I have below LINQ Query:

returnVal = context.ReservationRequests
   .Where(s => ((s.RequestStatusId.HasValue) &&
                (s.RequestStatusId.Value == ResStatusId)) &&
               ((string.IsNullOrEmpty(loggedInUserRole) 
                  || s.SubmitterGroupName == loggedInUserRole) 
                  ||(s.CreatedBy == ApplicationSecurityDirector.CurrentUserGuid)))                                                         
   .Skip(skip)
   .Take(take)
  .ToList();

What this LINQ query is supposed to do it look into the ReservationRequests table and look for records where RequestStatusId = (suppliedRequestStatusId) and SubmitterGroupName should be equal to the logged in user role (but there are cases where user is not assigned to any role) and it should also return any requests which are created by user. So basically return all records if assigned to a particular group and also the requests created by logged in person if any.

The above query works fine incases where user is logged in to a group but it does not return correct results when user is not assigned to any groups. In case person is not assigned to any group it should return any records which were CreatedBy the user.

Below is a SQL query that I wrote which returns the correct amount of records for all my cases and I basically need my LINQ to be like this sql but I am not sure what I am missing here.

     SELECT *
  FROM [MyDB].[dbo].[ReservationRequests]
  where 
  (RequestStatusId = 2) 
  and 
  (SubmitterGroupName != null or SubmitterGroupName = null 
  or createdby = 'C5188D45-TEST-45BE-8C04-123455733A31')

Can someone please look into my LINQ query and see why is it returning incorrect records than my SQL ? Thanks I been looking at this for a while now!

After all the suggestion here is my updated LINQ:

returnVal = context.ReservationRequests
.Where(s => ((s.RequestStatusId.HasValue) &&
(s.RequestStatusId.Value == ResStatusId)) &&
(s.SubmitterGroupName == loggedInUserRole ||
s.CreatedBy == ApplicationSecurityDirector.CurrentUserGuid))
.Skip(skip)
.Take(take)
.ToList();

So question: Will this query work in cases loggedInUserRole is null? In case loggedInUserRole is null then I just want to return records which are CreatedBy the logged in user.

Another Update: (9/22/2017) 9.54 AM So I ran that statement. It works fine in cases when user is assigned to a group but when user is not assigned to a group instead of showing just the requests opened by the logged in user it returns a lot more records.

Answer 1

incorrect records is relative... the records it's returning are correct I guess. We only can analyse what you're doing here and where the differences are:

In the linq query you search for

s.SubmitterGroupName == loggedInUserRole

in the SQL statement you search for

SubmitterGroupName != null or SubmitterGroupName = null 

SubmitterGroupName cant be null and not null at the same time.So I guess, loggedInUserRole is null. This is with or, so this is always true. You only search then for createdby = 'C5188D45-TEST-45BE-8C04-123455733A31'

plus, in the linq-query you

.Skip(skip).Take(take)

this is missing in your sql-statement

so I think what you want is:

returnVal = context.ReservationRequests
.Where(s => ((s.RequestStatusId.HasValue) &&
(s.RequestStatusId.Value == ResStatusId)) &&
(s.SubmitterGroupName == loggedInUserRole || (s.SubmitterGroupName == null && s.CreatedBy == ApplicationSecurityDirector.CurrentUserGuid)))
.Skip(skip)
.Take(take)
.ToList();

Answer 2

I am not entirely sure why you are adding all sorts of checks in there, but this should work:

returnVal = context.ReservationRequests
.Where(s => RequestStatusId == ResStatusId &&
    (s.SubmitterGroupName == loggedInUserRole || s.CreatedBy == ApplicationSecurityDirector.CurrentUserGuid)
.Skip(skip)
.Take(take)
.ToList();