How to do a "where in values" in LINQ-to-Entities 3.5

Contains is not supported in EF at this time.

Update: found out how to do this. And EF will generate the appropriate SQL on the database. I'm not sure if this is for EF4 only but I got the tip from Entity Framework 4.0 Recipes

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var listOfIds=GetAListOfIds();
var context=CreateEntityFrameworkObjectContext();
var results = from item in context.Items
              where listOfIds.Contains(item.Category.Id)
              select item;
//results contains the items with matching category Ids

This query generates the correct in clause on the server side. I haven't tested it with EF 3.5 but it does work with EF4.

NB: The values passed into the in clause are NOT parameters so make sure you validate your inputs.

It is somewhat of a shame that Contains is not supported in Linq to Entities.

IN and JOIN are not the same operator (Filtering by IN never changes the cardinality of the query).