如何减去LINQ to SQL中的两个日期？

Question

我想能够将dd添加到custQuery7。也就是说，从值大于3天前的trans_date中减去两个日期date_paid。然后数一下。

 var dd = m.date_paid.Value.Subtract(m.trans_date.Value) > 3; 

     var custQuery7 = ((from m in DataContext.pu_balance_hists 
          where m.desc_code == 141 
          && m.trans_date.Value.Year == 2016 
          && m.trans_date.Value.Month == 5 
          select m)).Count(); 

这里是SQL查询我试图模仿：

select COUNT(*) as 'UnprocessedChques' from pu_balance_hist 
where desc_code=141 and date_paid-trans_date>3 
and YEAR(trans_date)=2016 and MONTH(trans_date)=5 

Answer 1

没有测试，但你可以这样做：

var custQuery7 = ((from m in DataContext.pu_balance_hists 
         where m.desc_code == 141 
         && SqlMethods.DateDiffDay(m.date_paid, m.trans_date) >= 3 
         && m.trans_date.Value.Year == 2016 
         && m.trans_date.Value.Month == 5 
         select m)).Count(); 

https://msdn.microsoft.com/en-us/library/bb468730(v=vs.110).aspx