[Solved]-How to convert the SQL query into LINQ?-LINQ,C#

You can use a tool called LINQPad.

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hope this helps

from t in Temp_Nurse_Fill_RequestNumbers 
group by t.ShiftName, t.date
into g 
select new 
{
   Date = g.date,
   Score = (from tt in g select tt.Score).max
   IsPreferred = 1
};

Hmm, how about something like this (this is C#, I presume it is trivial to convert)

temps
    .GroupBy(x => new {x.ShiftName, x.Date})
    .Select(g => new TempNurseProjection
        {
            Date = g.Key.Date,
            ShiftName = g.Key.ShiftName,
            MaxScore = g.Max(q => q.Score),
            IsPreferred = true
        });

Just for convenience

tems.
    GroupBy(Function(x) New With { x.ShiftName, x.Date }).
    Select(Function(g) New TempNurseProjection With {
        .Date = g.Key.Date,
        .ShiftName = g.Key.ShiftName,
        .MaxScore = g.Max(Function(q) q.Score),
        .IsPreferred = True
    })

EDIT

Sorry didn't noticed that the final projection is not anonymous but named type.