Question

I have the following LINQ query. The problem is it’s returning 13k results when tblSurveys only has 20 total. What am I doing wrong?

from s in surveyContext.tblSurveys
from st in surveyContext.tblTypes_for_Surveys
from t in surveyContext.tblSurvey_Types
where (s.Survey_Date >= startDate && s.Survey_Date <= stopDate) && 
      (s.Unsubstantiated || 
         (st.SurveyID == s.SurveyID && st.SurveyTypeID == t.SurveyTypeID && 
         t.UnsubstantiatedAvailable && (from d in surveyContext.tblDeficiencies
                                         where d.SurveyID == s.SurveyID
                                        select d.DeficiencyID).Count() == 0))
orderby s.Survey_Date
select s;

Answer 1

Do you have foreign keys and relationships setup in your database? If so, you can greatly simplify your query. I’d also recommend renaming your tables in the .dbml file so they aren’t all prefixed with ‘tbl’.

If you do have relationships setup, your query could look (something) like this:

from s in surveyContext.tblSurveys
where (s.Survey_Date >= startDate && s.Survey_Date <= stopDate) && 
     (s.Unsubstantiated || 
        (s.tblTypes_for_Surveys.Any(st => st.tblSurvey_Type.UnsubstantiatedAvailable) && s.tblDeficiencies.Count() == 0))
orderby s.Survey_Date
select s;