.NET has had this since 2006. LINQ to SQL and Entity Framework both support LINQ expressions. The problem is that more and more .NET devs are shunning it when working their relational database. There is an adage that if you're working with SQL then you should just be writing directly in SQL. Everything else is second rate.
As long as an ORM allows you to break out and right custom optimised SQL when needed, then I see no reason to write all your SQL by hand. ORMs are great for covering basic, repetitive queries, but there are times where it's not producing what you need. Of course you then loose the portability feature of ORMs, but I think this is acceptable. The biggest advantage for me isn't generation of SQL, it's mapping data back into your domain model/DTOs.
Given the queries I had to code lately, I'll take ARel and ActiveRecord scopes composability any day instead of mashing SQL fragment strings together and hoping for the best.
