c# - GroupBy and Count with condition using LINQ -

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i have exam table, , examresults includes questions of specific exam. table contain question, answer selected, , answerpower indicate if answer correct or not:

  • 1 (means correct),
  • 0 (means wrong),
  • null (means not answered , considered wrong).

i trying count of wrong answers of specific exam grouped chapters.

the following give me count of answers grouped chapter, don't know set condition count wrong answers can answerpower!=1

                var query = ex.examresults                 .groupby(p => new             {                 p.question.chapter.chaptername,                 p.answerpower             })             .select(g => new             {                 g.key.chaptername,                 mistakes = g.count()             });

inside count can give condition below, note have removed answerpower groupby

  var query = ex.examresults         .groupby(p => new     {         p.question.chapter.chaptername     })     .select(g => new     {         g.key.chaptername,         mistakes = g.count(x => x.answerpower!=1),         correctanswers = g.count(x => x.answerpower==1)     });

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