Question

我有一个linq查询返回前12个月就好了

var Last12query = from ech in this.dbContext.EmployeeCheckHistories
                          where ech.CompanyID == GlobalVariables.CompanyID &&
                          ech.Employees.ClientID == GlobalVariables.Client
                          group ech by ech.CheckDate.Value.AddMonths(-12).Month into echG
                          orderby echG.Key ascending
                          select echG;

但是当我试图拉动前6个月时，它会返回相同的数据

var Last6query = from ech in this.dbContext.EmployeeCheckHistories
                          where ech.CompanyID == GlobalVariables.CompanyID &&
                          ech.Employees.ClientID == GlobalVariables.Client
                          group ech by ech.CheckDate.Value.AddMonths(-6).Month into echG
                          orderby echG.Key ascending
                          select echG;

我不确定为什么返回的数据仍然是12个月的价值。

这是我回来的JSON

[{"SeriesName":["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],"Value":[160536.62000,115787.74000,300994.32000,72237.43000,73189.97000,61357.57000,43790.03000,31074.86000,58405.69000,64351.36000,82715.84000,78962.98000]},
{"SeriesName":["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],"Value":[43790.03000,31074.86000,58405.69000,64351.36000,82715.84000,78962.98000,160536.62000,115787.74000,300994.32000,72237.43000,73189.97000,61357.57000]}]

Answer 1

您似乎没有过滤查询（where子句）只是分组，因此您始终可以获得按月分组的所有行。从一年前的同一个月的日期中减去12个monts，所以在你的情况下，当你只得到分组的月份数时，它没有任何效果。

如果你想要从今天起最后N个月的数据，你应该有这样的东西：

var dateLimit = DateTime.Today().AddMonths(-N);
...
where ech.CheckDate>=dateLimit
group ech by ech.CheckDate.Month()
...

Answer 2

通过为Last12query和Last6query编写的Linq，使用Group by是错误的，在Last6query的查询中，您刚刚将数据移至6个月前。不是本月的数据（你不会得到任何特定月份的正确数据），对于12个月的数据，它会没问题，因为你把它改了一年。您可以在数据中看到这一点。因为december-6 months将june，所以（任何月份 - 6个月）将是一个月。

因此，减去月份不是解决方案，请执行此查询。

var Last6query = from ech in this.dbContext.EmployeeCheckHistories
                      where ech.CompanyID == GlobalVariables.CompanyID &&
                      ech.Employees.ClientID == GlobalVariables.Client
                      where ech.CheckDate.Value.Month>DateTime.Today().AddMonths(-6)
                      group ech by ech.CheckDate.Value.Month into echG
                      orderby echG.Key ascending
                      select echG;

并在12个月内做同样的事情。因为你没有用月和年检查，否则它会显示年份错误（如果年份是2015年，它将显示2014年的结果）。

  var Last12query = from ech in this.dbContext.EmployeeCheckHistories
                      where ech.CompanyID == GlobalVariables.CompanyID &&
                      ech.Employees.ClientID == GlobalVariables.Client
                      where ech.CheckDate.Value.Month>DateTime.Today().AddMonths(-12)
                      group ech by ech.CheckDate.Value.Month into echG
                      orderby echG.Key ascending
                      select echG;

Linq查询未返回前6个月

2 个答案: