How to get Percentage of Sales for the Past 5 Years-CodePudding

In my ASP.NET Core-5 Entity Framework I have this model:

public class Sales
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Amount { get; set; }
    public DateTime? SalesDate { get; set; }
}

DTO:

public class YearlyPercentDto
{
    public decimal SalesTotal { get; set; }
    public int SalesPercent { get; set; }
    public string Year { get; set; }
}

public List<YearlyPercentDto> GetYearlySalesSummary()
{
    var salesDetail = _context.sales               
        .GroupBy(o => new
        {
            Year = o.CreatedDate.Value.Year
        })
        .Select(u => new YearlyPercentDto
        {
            SalesPercent = u.Sum(x => x.Amount),
            Year = u.Key.Year.ToString()
        }).ToList();
    return salesDetail;
}

I want to get the total_sales, percentage_sales for each year in the past 5 years as shown below:

Year (Past 5 Years)    SalesTotal     SalesPercent

2021                     200000       18
2020                     4300000
2019                     1290000
2018                     5400000 
2017                     3322220

How do I achieve this?

CodePudding user response：

I think I'd just pull the totals from the DB and have C# work out the percentage:

public List<YearlyPercentDto> GetYearlySalesSummary()
{
    var salesDetail = _context.sales
        .Where(s => o.CreatedDate > DateTime.Now.AddYears(-5)
        .GroupBy(o => o.CreatedDate.Value.Year)
        .Select(u => new YearlyPercentDto
          {
            SalesTotal = u.Sum(x => x.Amount),
            Year = u.Key.ToString()            //why is Year a string?
          }
        ).ToList();

    //grand total
    var tot = salesDetail.Sum(s => s.SalesTotal);

    //apply percentage to each element
    salesDetail.ForEach(s => s.SalesPercent = (int)(100.0 * s.SalesTotal/tot));

    return salesDetail;
}

There seems little point in bullying the DB to provide this info when C# can quickly work it out - the extra hoops to jump through to get the DB to do it don't seem worth it