Selecting first 100 records using Linq

Question

How can I return first 100 records using Linq?

I have a table with 40million records.

This code works, but it's slow, because will return all values before filter:

var values = (from e in dataContext.table_sample               where e.x == 1               select e)              .Take(100); 

Is there a way to return filtered? Like T-SQL TOP clause?

Answer 1

No, that doesn't return all the values before filtering. The Take(100) will end up being part of the SQL sent up - quite possibly using TOP.

Of course, it makes more sense to do that when you've specified an orderby clause.

LINQ doesn't execute the query when it reaches the end of your query expression. It only sends up any SQL when either you call an aggregation operator (e.g. Count or Any) or you start iterating through the results. Even calling Take doesn't actually execute the query - you might want to put more filtering on it afterwards, for instance, which could end up being part of the query.

When you start iterating over the results (typically with foreach) - that's when the SQL will actually be sent to the database.

(I think your where clause is a bit broken, by the way. If you've got problems with your real code it would help to see code as close to reality as possible.)