I'm sorry but I don't see what it has to do with lookups. Notice that I had 2 queries. Both of them had the same criteria. The only difference between them was that one of them used variables that got there values at the same scope as the query and the other one used the values directly. The one that used it directly did use seek operator and the one that used variables used a table scan (of course both of them returned the same records). If this would have been to avoid lookups, then both queries should have acted the same.

Also if I modify the queries and use dates that don't exist in the table (again for both queries) I still get index seek for the query that is not using the variables and table scan for query that is using the variables. This is because what I've explained before. The query plan is generated before runtime. The variables get there values during runtime, so when the server creates the query plan it has no idea about the values that will be used in the query so it estimates that 20% will be returned

Adi