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LINQ Equivalent Of Where IN

August 25th, 2008 | 8 Comments | Posted in Programming

Working with LINQ to SQL I came across a need of writing a LINQ query equivalent of  T-SQL “Where IN” clause. This is what T-SQL query looks like.

SELECT     CustomerID, CompanyName, ContactName, ContactTitle, Address,
           City, Region, PostalCode, Country, Phone, Fax
FROM       Customers
WHERE      (Country IN ('UK', 'USA', 'Australia'))

How do I write Where IN in LINQ?

Below is the query which can be used for a “WHERE IN” scenario. Query 1 uses query syntax and Query 2 uses lambda expression. I am using using a DataContext for Northwind database. See LINQ To SQL Tutorial to see how to generate a DataContext.

LINQ Query 1
string[] countries = new string[] { "UK", "USA", "Australia" };
var customers =
    from c in context.Customers
    where countries.Contains(c.Country)
    select c;
LINQ Query 2
string[] countries = new string[] { "UK", "USA", "Australia" };
var customers =
    context.Customers
    .Where(c => countries.Contains(c.Country));
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8 Responses to “LINQ Equivalent Of Where IN”

  1. curious Says:
     September 24th, 2008 at 11:58 pm

    couldn’t I write it that way?

    var customers = from c in context.Customers
    where (c.Country == “UK” || c.Country == “USA” ||
    c.Country == “Australia”)
    select c;

  2. Deepak Says:
     September 25th, 2008 at 7:45 am

    Yes that will also work.
    The solution I posted will also work when the elements of the array are unknown. Imagine this array being generated dynamically.

  3. LAD Says:
     October 15th, 2008 at 9:27 pm

    ArrayList is not supported

  4. Steve Says:
     January 5th, 2009 at 12:59 am

    This only works with strings ?

  5. Deepak Says:
     January 5th, 2009 at 9:04 am

    Hi Steve,

    Here is a post I wrote which shows you how to do this with integers. I hope you will find it useful.

    http://www.thereforesystems.com/linq-equivalent-of-where-in-with-int/

  6. Lucia Says:
     February 1st, 2009 at 10:10 pm

    Thank you, Deepak, very useful.

  7. Deepak Says:
     February 2nd, 2009 at 5:26 am

    Lucia,

    Thank you for the kind words.

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  1. LINQ Equivalent Of Where IN With Int | One .Net Way  January 5th, 2009

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