In VB.NET, which LINQ to SQL Left-Join method is best to use?

Is one of these VB.NET LINQ to SQL Left Join options superior to other?

I'm not sure which to use.

Method 1: Lambda

Dim query = From A In DB.Product_Categories
            From B In DB.MasItems.Where(Function(x) CBool(x.itemkey = A.ItemKey)).DefaultIfEmpty
            Select A.Name

Method 2: Group Join

Dim query = From A In DB.Product_Categories
            Group Joi开发者_开发百科n B In DB.MasItems On B.itemkey Equals A.ItemKey Into X = Group
            From Y In X.DefaultIfEmpty
            Select A.Name()

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The generated SQL is the same for both queries, so in LINQ to SQL it is really personal preference.

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EDIT: This is true for LINQ to Objects.
I don't know about LINQ to SQL.

Method 2 is faster, since GroupJoin builds a hashtable internally.

Method 1 is O(n2), since it needs to search all of MasItems for each category.