How Can I Group Data Into Weekdays?

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How can i group my data into days of week like
Saturday,Sunday,Monday,Tuesday,Wednesday,Thursday,Friday

using linq to Entity Framework.

Posted 15-Nov-14 18:10pm

shaprpuff

Updated 16-Nov-14 20:47pm

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Manas Bhardwaj 16-Nov-14 4:31am

And where is thrusday?

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DamithSL · Accepted Answer · 2014-11-15T18:18:00

Solution 1

you can use SqlFunctions.DatePart:[^]

C#

var results = data.GroupBy(i =>SqlFunctions.DatePart("weekday", i.DateFieldName));

check This similar question and answers for more information [^]

Posted 15-Nov-14 18:18pm

DamithSL

Updated 15-Nov-14 18:20pm

v2

Comments

Manas Bhardwaj 16-Nov-14 4:32am

Yes +5!

[no name] 16-Nov-14 7:13am

Wow! Looks very easy and straightforward +5.

shaprpuff 17-Nov-14 3:40am

This function can only be invoked from LINQ to Entities. Error accour when trying to use it in linq to entity

DamithSL 17-Nov-14 3:44am

can you show the code you tried?

shaprpuff 17-Nov-14 5:23am

public object valuefunc(List<emails> email)
{

var res = email.Where(p=>p.CurrentStatus=="Completed").GroupBy(p=>SqlFunctions.DatePart("weekday",
p.SubmitDate.Value));

return res.ToList();
}

DamithSL 17-Nov-14 5:31am

you need to do as below,
dbcontext.Emails.Where(p=>p.CurrentStatus=="Completed").GroupBy(p=>SqlFunctions.DatePart("weekday",
p.SubmitDate.Value));

then only you sending correct sql statement to database and get the results. what you are doing is load whole emails as List and then apply filter. that is inefficient. learn the basics of EF.

DamithSL 17-Nov-14 5:34am

in this case you can simply use normal C# date time function as 2nd answer explained. But that is LINQ not EF.

BillWoodruff · Accepted Answer · 2014-11-15T22:05:00

I have not used Entity FrameWork, but here's an example in Linq of grouping by DayOfWeek, and I assume this can be easily used with EF; to make it more fun I've filtered to return only groups of non-weekend days with more than one instance:

C#

private List<datetime> days = new List<datetime>();

private void TestGroupByDayOfWeekNotWeekend(object sender, EventArgs e)
{
    for (int i = 1; i < 31; i++)
    {
        int mod = i%7 + 1;
        days.Add(new DateTime(2014,11,mod));
    }

    var dayOfWeekGroups = days
        .Where(dy =>
         dy.DayOfWeek != DayOfWeek.Saturday && dy.DayOfWeek != DayOfWeek.Sunday)
        .GroupBy(dt => dt.DayOfWeek)
        .Where(grp => grp.Count() > 1);

    foreach (var grp in dayOfWeekGroups)
    {
        Console.WriteLine(grp.First().DayOfWeek.ToString());

        foreach (var dt in grp)
        {
            Console.WriteLine('\t' + dt.ToShortDateString());
        }

        Console.WriteLine();
    }
}