CODEWITHSUNDEEP
c#sqllinqentity-frameworklambda
Andrew
Andrew

Reputation: 5725

How to maintain LINQ deferred execution on SELECT TOP 1

How do I create a LINQ statement that maintains deferred execution when the SQL query contains select top 1? I want it to be chainable to other LINQ queries of type IQueryable<>.

var query1 = from t in table
             where t.test == 1
             select t;

//this should set query2 of type IQueryable<TableEntity> 
var query2 = from q in query1
             [[SELECT TOP 1 SOMEHOW]]
             select q;

var query3 = from q in query2
             where q.test2 == 2

var executedResult = query3.ToList();

Not fussed if the solution uses lambda or linq or both.

Upvotes: 1

Views: 127

Answers (2)

Mez
Mez

Reputation: 4726

Use the Take(1) which returns an IEnumerable. If the source is empty this may return a null. Check these links out for more information...

MSDN source : http://msdn.microsoft.com/de-de/library/bb503062(v=vs.110).aspx

In your case

var query2 = (from q in query1
         select t)
         .Take(1);

Upvotes: 1

Michał Krzemiński
Michał Krzemiński

Reputation: 1251

You can try this:

var query2 = (from q in query1
             select t)
             .Take(1);

Take(count) returns IEnumerable containing count elements (or less if it didn't find enough).

Upvotes: 3

Related Questions