Linq query with datatable [closed] - linq

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Closed 10 years ago.
I have this datatable result in c#
Date Employee Job1 Job2 Job3
1/1/2012 a 1 1 1
1/1/2012 b 2 2 2
1/1/2012 c 2 1 4
1/1/2012 d 4 2 1
1/2/2012 a 3 2 5
1/2/2012 b 2 2 2
1/2/2012 c 3 3 3
1/2/2012 d 1 1 1
1/3/2012 a 5 5 5
1/3/2012 b 2 2 6
1/3/2012 c 1 1 1
1/3/2012 d 2 3 4
2/1/2012 a 2 2 2
2/1/2012 b 5 5 2
2/1/2012 c 2 2 2
2/2/2012 a 3 3 3
2/2/2012 b 2 3 3
3/1/2012 a 4 4 2
Now I want a result like this:
Job1:
Employee January February March
A 9 5 4
B 6 7
C 6 2
D 7
Please, can anybody suggest me how to do this with "Linq" in c#?

Answer 1

This might work (or give you at least an idea):
var monthEmpGroups = tblEmpJobs.AsEnumerable()
.Select(r => new
{
Row = r,
Employee = r.Field<String>("Employee"),
Year = r.Field<DateTime>("Date").Year,
Month = r.Field<DateTime>("Date").Month
})
.GroupBy(x => x.Employee);
DataTable tblMonthResultJob1 = new DataTable();
tblMonthResultJob1.Columns.Add("Employee", typeof(string));
var dtf = System.Globalization.CultureInfo.CurrentCulture.DateTimeFormat;
foreach (var empGroup in monthEmpGroups)
{
string employee = empGroup.Key;
var newRow = tblMonthResultJob1.Rows.Add();
newRow["Employee"] = employee;
var empMonthGroup = empGroup.GroupBy(mg => new { mg.Year, mg.Month });
foreach (var empYearMonthGroup in empMonthGroup)
{
int year = empYearMonthGroup.Key.Year;
int month = empYearMonthGroup.Key.Month;
string colName = string.Format("{0} {1}", dtf.GetMonthName(month), year);
if (!tblMonthResultJob1.Columns.Contains(colName))
tblMonthResultJob1.Columns.Add(colName, typeof(int));
int empJob1Count = empYearMonthGroup.Sum(x => x.Row.Field<int>("Job1"));
newRow[colName] = empJob1Count;
}
}
// do the same for the other job types
Update If you need to add a "total-row" at the "end" as commented:
DataRow totalRow = tblMonthResultJob1.Rows.Add();
totalRow["Employee"] = "ALL";
var monthGroups = tblEmpJobs.AsEnumerable()
.Select(r => new {
Row = r,
Year = r.Field<DateTime>("Date").Year,
Month = r.Field<DateTime>("Date").Month
})
.GroupBy(x => new { x.Year, x.Month });
foreach (var monthGroup in monthGroups)
{
int yearAll = monthGroup.Key.Year;
int monthAll = monthGroup.Key.Month;
string colName = string.Format("{0} {1}", dtf.GetMonthName(monthAll), yearAll);
if (!tblMonthResultJob1.Columns.Contains(colName))
tblMonthResultJob1.Columns.Add(colName, typeof(int));
int allJob1Count = monthGroup.Sum(x => x.Row.Field<int>("Job1"));
totalRow[colName] = allJob1Count;
}
Update2
I am getting error system.dbnull on this line int
empJob1Count = empYearMonthGroup.Sum(x => x.Row.Field<int>("Job1"));
I think there
are some null values and it is not able to cast null values while
doing sum. Please help, how should i resolve this
You can use this code to default an int? to zero:
var empYearMonthCount = empYearMonthGroup.Sum(x =>
{
int? job1 = x.Row.Field<int?>("Job1");
int value = 0;
if(job1.HasValue) value = job1.Value;
return value;
});