如何将两个 linq 查询组合在一起以优化性能

Question

I have the following two queries which query from the database separately.

I understand that one Linq query is much better for optimising performance.

Would it be possible to do the combination of the two following queries?

result = GetAllJobModelsOrder(db.AllJobModel.Where(a => 
     a.JobTitle.Contains(searchTitle) 
  && a.locationName.Contains(searchLocation) 
  && (a.PostedDate == timesNow || a.PostedDate == time || a.PostedDate == time2 || a.PostedDate == time3 || a.PostedDate == time4 || a.PostedDate == time5 || a.PostedDate == time6 || a.PostedDate == time7))
.ToList());

result = (from app in result orderby DateTime.ParseExact(app.PostedDate, "dd/MM/yyyy", null) descending select app).ToList();

Answer 1

I have the following two queries which query from the database separately.

No you don't. The first query hits the database and passes the results to GetAllJobModelsOrder. The second query appears to be in-memory LINQ-to-Objects, filtering and sorting the results.

I understand that one Linq query is much better for optimising performance.

That is not always the case.