filter on multichoice column

Question

In my list i have multichoice column... How to filter on it programatically.. I know to filter based on text column like below

  SPList oList = oWebsiteRoot.Lists["mylist"]; // list_name
  SPQuery query = new SPQuery();
  query.Query = "<Where><And><Lt><FieldRef Name='ID'/>" + "<Value Type='Integer'>" + itemIndex + "</Value></Lt><Eq><FieldRef Name='Status'/>" +
                "<Value Type='Text'>Approved</Value></Eq></And></Where><OrderBy><FieldRef Name='ID' Ascending='False'></FieldRef></OrderBy>";
  SPListItemCollection items = null;
  items = oList.GetItems(query);
  return items;

But how to filter on multichoice column passing it comma seperate string .

I also tried using U2uCamlQuery Builder. But when i try to add filter it throws error "value cannot be null".

Update1 I tried below Query now

query.Query = "<Where><Or><Contains><FieldRef Name ='ExtName'/><Value Type ='MultiChoice'>Test1</Value></Contains><Contains><FieldRef Name ='ExtName'/><Value Type ='MultiChoice'>Test2</Value></Contains></Or></Where> ";

But it gives only records from value "Test1" even though there are records With value "Test2"

Answer 1

Without fully knowing your list data structure, I'm thinking your query string should be formatted along the lines of :

<Where>
      <Or>
         <Contains>
            <FieldRef Name='SeriousHarmQ1' />
            <Value Type='MultiChoice'>Loss of consciousness</Value>
         </Contains>
         <Contains>
            <FieldRef Name='SeriousHarmQ1' />
            <Value Type='MultiChoice'>Amputation of a body part</Value>
         </Contains>
      </Or>
   </Where>

As an alternative to U2UCamlQueryBuilder, I tend to use CAML Designer 2013, which works well for me.