How to properly get records from database with linq in c#

Question

I have a few filters, which they affect taking rows of items in consideration. Filters: DateFrom, DateTo, search (FirstName, LastName, Email)

here is the query

query = repository.GetAll("Location", "Service", "Employee")
        .Where(x => x.CompanyId == companyId && x.LocationId == locationId && !x.Deleted && x.IsConfirmed) //this Where clause works

        .Where (x => ((x.FirstName + " " + x.LastName).Contains(search) && !string.IsNullOrEmpty(x.FirstName)) || (x.EmailAddress).Contains(search) && !string.IsNullOrEmpty(x.EmailAddress) ||         
        ((x.Employee.FirstName).Contains(search) && !string.IsNullOrEmpty(x.Employee.FirstName))) //this caluse is causing the issue

        .Where(y => (((dateTimeFilterFrom.HasValue && y.Date >= dateTimeFilterFrom)) || !dateTimeFilterFrom.HasValue) && (((dateTimeFilterTo.HasValue && y.Date <= dateTimeFilterTo)) || !dateTimeFilterTo.HasValue)) //this where clause also works
        .OrderByDescending(x => x.Date).ThenByDescending(x => x.Start).Skip(itemsPerPage * (currentPage - 1)).Take(itemsPerPage);
}

List<Schedule> result = query.ToList();

return result;

https://i.imgur.com/KneJhf7.png

I would like to ignore it, if nothing is typed. Now it returns 0 rows, probably because I put wrong && statement somewhere

Cases:

1. I type in searchbox email or firstname or last name (from first column), and it should filter rows.
2. I dont type anything - I would like to ignore this clause with some expression func

This is .net 4.8

Answer 1

A much easier and quicker way is to have 2 different queries - one for a filtered result and one for a non-filtered result if the user does not type anything into the search field.

This check can be done locally and not in the database, which is cluttering your query.

Something like this should work (this excludes the extra .Where clauses you have for location/date/... filtering for brevity):

var shouldFilterData = !string.IsNullOrEmpty(search);

if (shouldFilterData)
        query = repository
                .GetAll("Location", "Service", "Employee")
                .Where(x => (x.FirstName + " " + x.LastName + " " + x.EmailAddress).Contains(search));
else
        query = repository
                .GetAll("Location", "Service", "Employee");

List<Schedule> result = query.ToList();
return result;