I want a query of entityframework method based

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I have a table like below

Bit	AId
true	1
false	1
false	2
true	2
true	1
false	3
true	1
false	3
false	1
true	2
true	1
true	3
false	3
true	2

suppose corresponding entity for above table is A.

I want a query entityframework method based that it subtract count of true from count of false for every unique AId. like below

Posted 28-Jul-14 6:03am

kave2011

Updated 28-Jul-14 6:15am

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Richard Deeming · Accepted Answer · 2014-07-28T06:22:00

How about something like this:

C#

IDictionary<int, int> result = context.A
    .GroupBy(a => a.AId, (AId, list) => new 
    { 
        AId, 
        TrueCount = list.Count(i => i.Bit), 
        FalseCount = list.Count(i => !i.Bit) 
    })
    .ToDictionary(x => x.AId, x => x.TrueCount - x.FalseCount)
;

Edit: Dictionaries do not preserve the order of the elements. If you want to use OrderBy, you'll need to use a difference collection type.

C#

var result = context.A
    .GroupBy(a => a.AId, (AId, list) => new
    {
        AId,
        Count = list.Count(i => i.Bit) - list.Count(i => !i.Bit)
    })
    .OrderBy(x => x.Count)
    .ToList()
;

// "result" now contains a sorted list of anonymous types,
// each of which has the properties "AId" and "Count".