How to SELECT WHERE NOT EXIST using LINQ?

C#SqlLinqEntity Framework

C# Problem Overview


I have to list all "shift" data to be assigned to an "employee" but shift data must not be included if it is already existing in employee's data. Let's see the image sample.

No filtering yet

This query solves the problem. I found this here:
Scott's Blog

select * from shift where not exists 
(select 1 from employeeshift where shift.shiftid = employeeshift.shiftid
and employeeshift.empid = 57);  

Let's see the result:

Filtered

Now my question is, how could I make this in linQ ? I'm using entity framework.
Hope someone could help. Thanks a lot!!!

C# Solutions


Solution 1 - C#

from s in context.shift
where !context.employeeshift.Any(es=>(es.shiftid==s.shiftid)&&(es.empid==57))
select s;

Hope this helps

Solution 2 - C#

The outcome sql will be different but the result should be the same:

var shifts = Shifts.Where(s => !EmployeeShifts.Where(es => es.ShiftID == s.ShiftID).Any());

Solution 3 - C#

First of all, I suggest to modify a bit your sql query:

 select * from shift 
 where shift.shiftid not in (select employeeshift.shiftid from employeeshift 
                             where employeeshift.empid = 57);

This query provides same functionality. If you want to get the same result with LINQ, you can try this code:

//Variable dc has DataContext type here
//Here we get list of ShiftIDs from employeeshift table
List<int> empShiftIds = dc.employeeshift.Where(p => p.EmpID = 57).Select(s => s.ShiftID).ToList();

//Here we get the list of our shifts
List<shift> shifts = dc.shift.Where(p => !empShiftIds.Contains(p.ShiftId)).ToList();

Solution 4 - C#

How about..

var result = (from s in context.Shift join es in employeeshift on s.shiftid equals es.shiftid where es.empid == 57 select s)

Edit: This will give you shifts where there is an associated employeeshift (because of the join). For the "not exists" I'd do what @ArsenMkrt or @hyp suggest

Solution 5 - C#

        Dim result2 = From s In mySession.Query(Of CSucursal)()
                      Where (From c In mySession.Query(Of CCiudad)()
                             From cs In mySession.Query(Of CCiudadSucursal)()
                             Where cs.id_ciudad Is c
                             Where cs.id_sucursal Is s
                             Where c.id = IdCiudad
                             Where s.accion <> "E" AndAlso s.accion <> Nothing
                             Where cs.accion <> "E" AndAlso cs.accion <> Nothing
                             Select c.descripcion).Single() Is Nothing
                      Where s.accion <> "E" AndAlso s.accion <> Nothing
                      Select s.id, s.Descripcion

Attributions

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionfiberOpticsView Question on Stackoverflow
Solution 1 - C#Arsen MkrtchyanView Answer on Stackoverflow
Solution 2 - C#hypView Answer on Stackoverflow
Solution 3 - C#CeridanView Answer on Stackoverflow
Solution 4 - C#Matt RobertsView Answer on Stackoverflow
Solution 5 - C#julioView Answer on Stackoverflow