Sounds like you've worked with poor code/developers. LINQ with EF translates into DB queries including aggreations and transformations. That's the whole point of compiling the query, unless someone either didn't understand the query they were writing or explicitly chose client-side evaluation.

Hello. LINQ isn't at all limited to LINQ-to-SQL. That is simply one of the numerous IQueryable providers, which is also possible to implement yourself by doing some expression parsing.

And for the record I hate LINQ to SQL.