CAML query, only want to render days in Calendar

Question

I'm new in CAML. I try to learn it. I want to render a day's on ASP Calendar. Have got a list with 5 colums/fields:

 Kontrakt | Pracownik | Dzien | ID | Procenty
 --------------------------------------------

When I render tradicional it's geting too long. When It has got more then 1000 element's it's getting 4-5 secounds. I want make Query which only gives me a day's withouts another colums/fields. I mahe a Query, in U2U Query Builder, but it gives me back all fields, and only I want a dates.

<Query> <Where> <And> <Lt> <FieldRef Name='Dzien' /> <Value Type='DateTime'>[Today+30Day(s)]</Value> </Lt> <Gt> <FieldRef Name='Dzien' /> <Value Type='DateTime'>[Today-30Day(s)]</Value> </Gt> </And> </Where> </Query>  

How to make a Query with only one field Dzien. Please help

Answer 1

Following is using SPQuery to return specific fields...

    SPQuery query = new SPQuery();
    query.Query = "<Where> <And> <Lt> <FieldRef Name='Dzien' /> <Value Type='DateTime'>[Today+30Day(s)]</Value> </Lt> <Gt> <FieldRef Name='Dzien' /> <Value Type='DateTime'>[Today-30Day(s)]</Value> </Gt> </And> </Where>"; // You can add some condition. Items returned by query
    query.ViewFields = String.Format("<FieldRef Name='{0}'/>", "Dzien"); //Fields returned by query

    SPListItemCollection itemCollection = myList.GetItems(query);

If you want multiple columns, you can specify adding more <FieldRef Name='fieldName' />

Also, for performance you can create Indexes on columns involved in Query for better performance:

You can read Indexing and Query Throttling here