Difference between two date in minutes
Joined: 17-Jan-2012
Mmm. there are some things to note about your query:
-
It seems that you have an extra ")" that shouln't be there. Please double check that.
-
There is no a function mapping that would work on (someDate - someDate) or Substract. Then there is no function mapping that would return a TotalMinutes. Read here to know the supported built-in Linq function mappings. So you have to write your own function mapping. Example:
public class MyDBFunctions
{
public static int DateDiffInMinutes(DateTime dateStart, DateTime dateEnd)
{
return 0;
}
}
public class MyDBFunctionMappings : FunctionMappingStore
{
public MyDBFunctionMappings ()
: base()
{
this.Add(new FunctionMapping(typeof(MyDBFunctions), "DateDiffInMinutes", 2, "DATEDIFF(minute, {0}, {1})"));
}
}
.. then in your code (I reformatted it a little bit):
lmd.CustomFunctionMappings = new MyDBFunctionMappings();
var query =
(
from q in lmd.Employes
join tEmployesTimeSheet in lmd.EmployesTimeSheet on q.EmployesCode equals tEmployesTimeSheet.EmployesCode
into groupJoinEmployesTimeSheet
from gEmployesTimeSheet in groupJoinEmployesTimeSheet.DefaultIfEmpty()
group new { q, tEmployesTimeSheet } by new
{
q.EmployesCode,
q.FirstName,
q.LastName
} into g
select new
{
g.Key.EmployesCode,
g.Key.FirstName,
g.Key.LastName,
EmployesTotalMinutesTimeSheet =
g.Sum(p => MyDBFunctions.DateDiffInMinutes(p.gEmployesTimeSheet.timeEnd.Value, p.gEmployesTimeSheet.timeStart))
}).ToList();
Hope helpful 
Joined: 17-Jan-2012
Thanks daelmo for your help
Now I see why the time operation was not working. The last extra ")" was a typo error, sorry.
I want to be as flexible as possible, so that my system can run on MS SQL Server, MySQL and MS Access for the worst.
If I write my own mapping function I loose this compatibility.
In conclusion, do you plan shortly supporting more timepsan and date operation ?
Best regards, Martin
