I'm trying to select users ids from custom tasks lists. All users are in one SP Group and I need to collect users Ids that doesn't have tasks.
query.Query = string.Format("<And><Membership Type='SPGroup' ID='{0}'><FieldRef Name='AssignedTo'/></Membership><Neq><FieldRef Name='AssignedTo'/><Value Type='Integer'><UserID/></Value></Neq></And>", web.SiteGroups[Groups.CodeConductGroup].ID);
var list = web.Lists[Lists.CodeConductTasks].GetItems(query);
Unfortunately this query returns me users ids that has tasks. Could anyone help to make it work in a right way?