How to use Linq to search for set of codes similarly "where in" in SQL

Question

Can anyone help how to use the associated search using linq ("where in" in sql)?

Linq Where search follows here,

1. select * from tablename where code = 'code1'
`string[] numbers = { "one", "two", "three", "four" };

string searchNumber = "two";
var number = from number1 in numbers
                     where number1 == searchNumber
                     select number1;

foreach (var n in number)
    Console.WriteLine(n);

        Console.ReadLine();`

How to search the set of codes using LINQ?

2. select * from tablename where code in ('code1','code2')

possible duplicate of [Where IN clause in LINQ](http://stackoverflow.com/questions/959752/where-in-clause-in-linq) — Davide Piras, Aug 09 '12 at 12:22

Nikhil Agrawal · Answer 1 · 2012-08-09T12:29:33.007

2

For first answer use this

var result = tablename.Where(x => x.code == "code1");

For second answer use this

List<string> str = new List<string>(){ "code1" , "code2" };

var result = tablename.Where(x => str.Contains(x.code));

edited Aug 09 '12 at 12:29

answered Aug 09 '12 at 12:23

Nikhil Agrawal

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score 1 · Answer 2 · answered Aug 09 '12 at 12:22

1

Try something along the lines of..

string[] codes = { "code1", "code2" };
var selections = tablename.Where(x => codes.Contains(x.code));

answered Aug 09 '12 at 12:22

Carson63000

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score 0 · Answer 3 · answered Aug 09 '12 at 12:21

0

string[] searchNumber = {"two","one"};
        var number = from number1 in numbers
                     where searchNumbers.Contains(number1)
                     select number1;

        foreach (var n in number)
        {
            Console.WriteLine(n);
        }

        Console.ReadLine();

That should do the trick.

answered Aug 09 '12 at 12:21

KyorCode

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If the input is string searchNumber = "'two','three'"; – user1531248 Aug 09 '12 at 12:23

score 0 · Answer 4 · answered Aug 09 '12 at 12:22

It depends on what you're going against. If you're using Entity Framework then you're going to need to look up creating an In statement. If you're just using Linq against an IEnumerable, contains will do what you want.

The reason being that if you're executing this against a database, the provider has to have implemented the Contains. Entity Framework doesn't IIRC.

score 0 · Answer 5 · answered Aug 09 '12 at 12:26

0

You need to invert the way you're thinking about this. Ask if numbers.Contains(searchNumber). Something like:

var result = from n in numbers
                 where numbers.Contains(searchNumber)
                 select n;

answered Aug 09 '12 at 12:26

Alvaro Rodriguez

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How to use Linq to search for set of codes similarly "where in" in SQL

5 Answers5