的LINQ留下了不平凡的条件加入

Question

，这是好的，它会产生一个左连接

var q = 
    from c in categories 
    join p in products 
    on c equals p.Category into ps 
    from p in ps.DefaultIfEmpty() 
    select new { Category = c, ProductName = p == null ? "(No products)" : p.ProductName }; 

可是你知道，如果我想要做这样的事情：

... 
on p.date between c.startdate and c.enddate 
... 

Answer 1

var q = 
    from c in categories 
    join p in products 
    on c equals p.Category into ps 
    from p in ps.DefaultIfEmpty() 
    where p.date >= c.startdate && p.date <= c.enddate 
    select new { Category = c, ProductName = p == null ? "(No products)" : p.ProductName };