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c#asp.net-mvc-3entity-frameworkentity-framework-4

Entity Framework multiple counts with a single query


Sorry if this has been asked, but how can I improve the following with a single call to the database?

var statsModel = new
{
     Total = _db.Messages.Count(),
     Approved = _db.Messages.Count(x => x.Approved),
     Rejected = _db.Messages.Count(x => !x.Approved),
};

Solution

  • First of all you can compute the Rejected by Total and Accepted like this:

    Rejected = Total - Approved
    

    And for further improvement you can compute both of them in one shot;

    from m in _db.Messages
    let Total =  _db.Messages.Count()
    let Accept = _db.Messages.Count(x => x.Approved == true)
    select new {Total , Accept})
    

    UPDATE: a simple hack for now : just take the first row

    (from m in _db.Messages
    let Total =  _db.Messages.Count()
    let Accept = _db.Messages.Count(x => x.Approved == true)
    select new {Total , Accept}).Take(1);
    

    But I'm looking for a cleaner one