Linq查询从开始日期和结束日期明智地获取Group By Date。 [英] Linq Query to get Group By Date wise From Start and End Dates.

问题描述

  public  IEnumerable< LoanReportViewModel> GetGroupByLoansOnDailyBasis（DateTime？StartDate，DateTime？EndDate）
 {
  var  circulationLoans = _circulation.All（）。Where（l = >  l.CreatedDate >  = StartDate&& l.CreatedDate  <  = EndDate）。ToList（）
 .GroupBy（c = >   new  DateTime（c.CreatedDate.Year，c.CreatedDate.Month， 1 ））。ToDictionary（g = > ;  g.Key.Date，g = >  g.Count（））; 
 
  return  circulationLoans.Select（g = >   new  LoanReportViewModel（）
 
 {
 LoanCreatedDate = g.Key.ToString（），
 LoansCount = g.Value 
} ）; 
 
} 

i希望看到结果如

日期= 01/06/2015，计数= 2

日期= 02/06/2015，计数= 3

日期= 03/06 / 2015，Count = 10

Date = 04/06/2015，Count = 5



但我只是贷款日期为

日期= 01/06/2015，总计数= 20 因为它正在循环所有计数内部 GroupBy函数（）并在最后汇总，并将密钥和值计数填充到查询结果。我还想根据日期范围按周和每月基础对这些结果进行分组。

解决方案

var loanRecords =来自_circulation.Where中的记录（x => x。 CreatedDate.Date> = x.StartDate.Date && x.CreatedDate.Date< = EndDate.Date）

记录组记录.CreatedDate.Date到groupRecords

选择新的

{

LoanDate = groupRecords.First（）。CreatedDate.Date，

LoanCount = groupRecords.Count（）

} .ToList（）;

试试这个：

 返回 _circulation.All（）
。其中（l = >  l.CreatedDate >  = StartDate&& l.CreatedDate <  = EndDate） 
 .GroupBy（c = >  c.CreatedDateToString（  yyyy / MM / dd））
。选择（g = >   new  LoanReportViewModel（）
 {
 LoanCreatedDate = g.Key，
 LoansCount = g.Count（）
}）。ToList（）; 

public IEnumerable<LoanReportViewModel> GetGroupByLoansOnDailyBasis(DateTime? StartDate, DateTime? EndDate)
        {
            var circulationLoans = _circulation.All().Where(l => l.CreatedDate >= StartDate && l.CreatedDate <= EndDate).ToList()
                .GroupBy(c => new DateTime(c.CreatedDate.Year, c.CreatedDate.Month, 1)).ToDictionary(g => g.Key.Date, g => g.Count());
            
            return circulationLoans.Select(g => new LoanReportViewModel()

            {
                LoanCreatedDate = g.Key.ToString(),
                LoansCount = g.Value
            });

        }

i want to see the result like
Date = 01/06/2015, Count=2
Date = 02/06/2015, Count=3
Date = 03/06/2015, Count=10
Date = 04/06/2015, Count=5

but i am Getting only The Loan Date as
Date = 01/06/2015 and total count =20 because it is looping all the counts Inside GroupBy Function() and sum it up at the end and than it populates the Key and Value Count to Query Result. i also want to Group these Results by Weekly and Monthly Basis From the Date Ranges.

解决方案

var loanRecords = from records in _circulation.Where(x => x.CreatedDate.Date >= x.StartDate.Date && x.CreatedDate.Date <= EndDate.Date)
group records by records.CreatedDate.Date into groupRecords
select new
{
LoanDate = groupRecords.First().CreatedDate.Date,
LoanCount = groupRecords.Count()
}.ToList();

Try this:

return _circulation.All()
    .Where(l => l.CreatedDate >= StartDate && l.CreatedDate <= EndDate)
    .GroupBy(c => c.CreatedDateToString("yyyy/MM/dd"))
    .Select(g => new LoanReportViewModel()
        {
            LoanCreatedDate = g.Key,
            LoansCount = g.Count()
        }).ToList();

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