Linq version of SQL "IN" statement

Question

I have the following 3 tables as part of a simple "item tagging" schema:

==Items==

• ItemId int
• Brand varchar
• Name varchar
• Price money
• Condition varchar
• Description varchar
• Active bit

==Tags==

• TagId int
• Name varchar
• Active bit

==TagMap==

• TagMapId int
• TagId int (fk)
• ItemId int (fk)
• Active bit

I want to write a LINQ query to bring back Items that match a list of tags (e.g. TagId = 2,3,4,7). In my application context, examples of items would be "Computer Monitor", "Dress Shirt", "Guitar", etc. and examples of tags would be "electronics", "clothing", etc. I would normally accomplish this with a SQL IN Statement.

Answer 1

Something like

var TagIds = new int[] {12, 32, 42};

var q = from map in Context.TagMaps 
        where TagIds.Contains(map.TagId)
        select map.Items;

should do what you need. This will generate an In ( 12, 32, 42 ) clause (or more specifically a parameterized IN clause if I'm not mistaken).

Answer 2

given array of items:

var list = new int[] {2,3,4}

use:

where list.Contains(tm.TagId)