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Entity LINQ query to slow

I'm new to the C#, I have a database that someone else designed, query works great, but compared with SQL, it's 10 times slower.
I made mistakes here for sure, anybody have tips to speed this up a little bit. This model is for displaying in table, and I converting int to ENUM and calculating discount for display.
Code is:
var results = from w in db.Washes.AsEnumerable()
join t in db.Wash_Types.AsEnumerable() on w.WashTypeId equals t.Id
join a in db.Accounts.AsEnumerable() on w.AccountId equals a.Id
orderby w.Id descending
select new AllWashesTable
{
Id = w.Id,
WashTime = w.WashTime,
WashTimeEnd = w.WashTimeEnd,
Name = a.Name,
Client = (w.Client != null ? w.Client.Naziv : ""),
MobileNumber = a.MobileNumber,
Identification = w.Identification,
WashType = WashTypeShowEnum.WashTypeShowEnumToString((WashTypeShowEnum.WashType) w.WashTypeId),
Price = int.Parse(t.WashPrice) * (1 - w.Discount) + "",
Discount = w.Discount
};
return results.ToList();
Seems all my entity queries are at least 5+ times slower than SQL. Somewhere I am making some mistake.

Your problem is the use of AsEnumerable. When the query gets executed (in your case the results.ToList()), Everything that appears after it, will be evaluated using linq-to-objects. It means that your joins will not be handled by DB. You will fetch all the records from the tables.
However, your function WashTypeShowEnum.WashTypeShowEnumToString will not be recognized by entity framework.
You might want to move the AsEnumerable to the end and then select the results.
var results = (from w in db.Washes
join t in db.Wash_Types on w.WashTypeId equals t.Id
join a in db.Accounts on w.AccountId equals a.Id
orderby w.Id descending
select new {w, a, t}).AsEnumerable().Select(arg=> new AllWashesTable
{
Id = arg.w.Id,
WashTime = arg.w.WashTime,
WashTimeEnd = arg.w.WashTimeEnd,
Name = arg.a.Name,
Client = (arg.w.Client != null ? arg.w.Client.Naziv : ""),
MobileNumber = arg.a.MobileNumber,
Identification = arg.w.Identification,
WashType = WashTypeShowEnum.WashTypeShowEnumToString((WashTypeShowEnum.WashType) arg.w.WashTypeId),
Price = int.Parse(arg.t.WashPrice) * (1 - arg.w.Discount) + "",
Discount = arg.w.Discount
};
return results.ToList();

LINQ query with a where condition containing

I am just learning LINQ and I have come across and issue Im not sure how to do in LINQ.
string numbers = "1,3,4,5";
string[] outletsInaStringArray = outlets.Split(',');
List<string> numbersAsAList = outletsInaStringArray.ToList();
I have a field in my database which holds a number. I only want to select the lines WHERE the number in the database is IN the line list of numbers "1,3,4,5" (these numbers are just examples).
Thanks in advance
I have looked at Tim and James answers and also looked at the line that James has sent. Im still a bit confused.....Sorry. Below is my actual code. It compiles but does not work
string outlets = "1,3,4,5"
string[] outletsNeeded = outlets.Split(',');
List<string> outletsNeededList = outletsNeeded.ToList();
DashboardEntities1 db = new DashboardEntities1();
var deptSalesQuery = (
from d in db.DashboardFigures
where (d.TypeOfinformation == "DEPTSALES") && (outletsNeeded.ToString().Contains(d.OutletNo.ToString()))
select new DeptSales
{
Dn = (int)d.Number,
Dnm = "Mens",
On = d.OutletNo,
Qs = (double)d.Value_4,
Se = (double)d.Value_2,
Si = (double)d.Value_3
}
);
In the DASHBAORDFIGURES table in SQL I have 2 records where the outlets number = 1, and therefore should have come up with two records.
Sorry if this is a simple thing, its just new to me and its frustrating.

You can use Contains as tagged:
var query = db.Table
.Where(x => outletsInaStringArray.Contains(x.Number) && x.information == "SALES");
that was method syntax, if you prefer query syntax:
var query = from figure in db.Figures
where outletsInaStringArray.Contains(figure.number)
&& figure.information == "SALES"
select figure;
But the column number is int, the List<string> stores strings, maybe your LINQ provider does not support .Contains(figure.ToString()). Then convert the strings to int first:
List<int> outletsNeededList = outletsNeeded.Select(int.Parse).ToList();

The answer that Tim provided is one method. Linq and lambda are interchangeable. Have a look at the following posting as well. Link
var result = from x in db.Table.ToList()
where outletsInaStringArray.Contains(x.Number)
select x;
Also have a look the following as it offers a very similar solution to the one you are looking for:
Link

As per i understand, you want to fetch data in similar way as IN (SQL) clause does it.
SELECT <Field_List>
FROM Table
WHERE IntegerField IN (1,2,4,5)
But i'm wondering why do you want to do it that way, when you can join data and get only matches. The worse is that you're trying to mix different data type and pass comma delimited text as a set of integers (i may be wrong):
SELECT <Field_List>
FROM Table
WHERE IntegerField IN ("1,2,4,5")
Above query won't execute, because the set of integers is "packed" into comma delimited string. To be able to execute that query, a conversion between data types must be done. Numbers in a string have to be converted to a set of integers (using user define split function or Common Table Expression):
;WITH CTE AS
(
--here convertion occurs
)
SELECT t2.<Field_List>
FROM CTE As t1 INNER JOIN TableName AS t2 ON t1.MyNumber = t2.IntegerField
Linq + any programming language is more flexible. You can build a list of integers (List) to build query.
See simple example:
void Main()
{
List<MyData> data = new List<MyData>{
new MyData(1,10),
new MyData(2, 11),
new MyData(5, 12),
new MyData(8, 13),
new MyData(12, 14)
};
//you're using comma delimited string
//string searchedNumbers = "1,3,4,5";
//var qry = from n in data
// join s in searchedNumbers.Split(',').Select(x=>int.Parse(x)) on n.ID equals s
// select n;
//qry.Dump();
List<int> searchedNumbers = new List<int>{1,2,4,5};
var qry = from n in data
join s in searchedNumbers on n.ID equals s
select n;
qry.Dump();
}
// Define other methods and classes here
class MyData
{
private int id = 0;
private int weight = 0;
public MyData(int _id, int _weight)
{
id = _id;
weight = _weight;
}
public int ID
{
get{return id;}
set {id = value;}
}
public int Weight
{
get{return weight;}
set {weight = value;}
}
}
Result:
ID Weight
1 10
5 12
Cheers
Maciej

Thank you all iv now got it to work using all your suggestions
the final code that works is as follows
DeptSales myDeptSales = new DeptSales(); // Single department
List<DeptSales> myDeptSalesList = new List<DeptSales>(); // List of Departments
DashboardEntities1 db = new DashboardEntities1();
var deptSalesQuery = from d in db.DashboardFigures
join s in outlets.Split(',').Select(x => int.Parse(x)) on d.OutletNo equals s
where (d.TypeOfinformation == "DEPTSALES")
select new DeptSales
{
Dn = (int)d.Number,
Dnm = "Mens",
On = d.OutletNo,
Qs = (double)d.Value_4,
Se = (double)d.Value_2,
Si = (double)d.Value_3
};
Thanks once again.

LINQ query optimization

I retrieve data from two different repositories:
List<F> allFs = fRepository.GetFs().ToList();
List<E> allEs = eRepository.GetEs().ToList();
Now I need to join them so I do the following:
var EFs = from c in allFs.AsQueryable()
join e in allEs on c.SerialNumber equals e.FSerialNumber
where e.Year == Convert.ToInt32(billingYear) &&
e.Month == Convert.ToInt32(billingMonth)
select new EReport
{
FSerialNumber = c.SerialNumber,
FName = c.Name,
IntCustID = Convert.ToInt32(e.IntCustID),
TotalECases = 0,
TotalPrice = "$0"
};
How can I make this LINQ query better so it will run faster? I would appreciate any suggestions.
Thanks

Unless you're able to create one repository that contains both pieces of data, which would be a far preferred solution, I can see the following things which might speed up the process.
Since you'r always filtering all E's by Month and Year, you should do that before calling ToList on the IQueryable, that way you reduce the number of E's in the join (probably considerably)
Since you're only using a subset of fields from E and F, you can use an anonymous type to limit the amount of data to transfer
Depending on how many serialnumbers you're retrieving from F's, you could filter your E's by serials in the database (or vice versa). But if most of the serialnumbers are to be expected in both sets, that doesn't really help you much further
Reasons why you might not be able to combine the repositories into one are probably because the data is coming from two separate databases.
The code, updated with the above mentioned points 1 and 2 would be similar to this:
var allFs = fRepository.GetFs().Select(f => new {f.Name, f.SerialNumber}).ToList();
int year = Convert.ToInt32(billingYear);
int month = Convert.ToInt32(billingMonth);
var allEs = eRepository.GetEs().Where(e.Year == year && e.Month == month).Select(e => new {e.FSerialNumber, e.IntCustID}).ToList();
var EFs = from c in allFs
join e in allEs on c.SerialNumber equals e.FSerialNumber
select new EReport
{
FSerialNumber = c.SerialNumber,
FName = c.Name,
IntCustID = Convert.ToInt32(e.IntCustID),
TotalECases = 0,
TotalPrice = "$0"
};

LINQ-To-SQL - slow query

I'm just wondering if anyone can offer any advice on how to improve my query.
Basically, it'll be merging 2 rows into 1. The only thing the rows will differ by is a 'Type' char column ('S' or 'C') and the Value. What I want to do is select one row, with the 'S' value and the 'C' value, and calculate the difference (S-C).
My query works, but it's pretty slow - it takes around 8 seconds to get the results, which is not ideal for my application. I wish I could change the database structure but I can't sadly!
Here is my query:
var sales = (from cm in dc.ConsignmentMarginBreakdowns
join sl in dc.SageAccounts on new { LegacyID = cm.Customer, Customer = true } equals new { LegacyID = sl.LegacyID, Customer = sl.Customer }
join ss in dc.SageAccounts on sl.ParentAccount equals ss.ID
join vt in dc.VehicleTypes on cm.ConsignmentTripBreakdown.VehicleType.Trim() equals vt.ID.ToString() into vtg
where cm.ConsignmentTripBreakdown.DeliveryDate >= dates.FromDate && cm.ConsignmentTripBreakdown.DeliveryDate <= dates.ToDate
where (customer == null || ss.SageID == customer)
where cm.BreakdownType == 'S'
orderby cm.Depot, cm.TripNumber
select new
{
NTConsignment = cm.NTConsignment,
Trip = cm.ConsignmentTripBreakdown,
LegacyID = cm.LegacyID,
Costs = dc.ConsignmentMarginBreakdowns.Where(a => a.BreakdownType == 'C' && a.NTConsignment == cm.NTConsignment && a.LegacyID == cm.LegacyID && a.TripDate == cm.TripDate && a.Depot == cm.Depot && a.TripNumber == cm.TripNumber).Single().Value,
Sales = cm.Value ?? 0.00m,
Customer = cm.Customer,
SageID = ss.SageID,
CustomerName = ss.ShortName,
FullCustomerName = ss.Name,
Vehicle = cm.ConsignmentTripBreakdown.Vehicle ?? "None",
VehicleType = vtg.FirstOrDefault().VehicleTypeDescription ?? "Subcontractor"
});

A good place to start when optimizing Linq to SQL queries is the SQL Server Profiler. There you can find what SQL code is being generated by Linq to SQL. From there, you can toy around with the linq query to see if you can get it to write a better query. If that doesn't work, you can always write a stored procedure by hand, and then call it from Linq to SQL.

There really isn't enough information supplied to make an informed opinion. For example, how many rows in each of the tables? What does the generated T-SQL look like?
One thing I would suggest first is to take the outputted T-SQL, generate a query plan and look for table or index scans.

LINQ group by month question

I'm new to LINQ to SQL and I would like to know how to achieve something like this in LINQ:
Month Hires Terminations
Jan 5 7
Feb 8 8
Marc 8 5
I've got this so far, and I think there is something wrong with it but I'm not sure:
from term1 in HRSystemDB.Terminations
group term1 by new { term1.TerminationDate.Month, term1.TerminationDate.Year } into grpTerm
select new HiresVsTerminationsQuery
{
Date = Criteria.Period,
TerminationsCount = grpTerm.Count(term => term.TerminationDate.Month == Criteria.Period.Value.Month),
HiresCount = (from emp in HRSystemDB.Persons.OfType<Employee>()
group emp by new { emp.HireDate.Month, emp.HireDate.Year } into grpEmp
select grpEmp).Count(e => e.Key.Month == Criteria.Period.Value.Month)
});
Thanks in advance.

I'm not quite sure where does the Criteria.Period value come from in your sample query.
However I think you're trying to read both hires and terminations for all available months (and then you can easily filter it). Your query could go wrong if the first table (Termination) didn't include any records for some specified month (say May). Then the select clause wouldn't be called with "May" as the parameter at all and even if you had some data in the second table (representing Hires), then you wouldn't be able to find it.
This can be elegantly solved using the Concat method (see MSDN samples). You could select all termniations and all hires (into a data structure of some type) and then group all the data by month:
var terms = from t in HRSystemDB.Terminations
select new { Month = t.TerminationDate.Month,
Year = term1.TerminationDate.Year,
IsHire = false };
var hires = from emp in HRSystemDB.Persons.OfType<Employee>()
select new { Month = emp.HireDate.Month,
Year = emp.HireDate.Year
IsHire = true };
// Now we can merge the two inputs into one
var summary = terms.Concat(hires);
// And group the data using month or year
var res = from s in summary
group s by new { s.Year, s.Month } into g
select new { Period = g.Key,
Hires = g.Count(info => info.IsHire),
Terminations = g.Count(info => !info.IsHire) }
When looking at the code now, I'm pretty sure there is some shorter way to write this. On the other hand, this code should be quite readable, which is a benefit. Also note that it doesn't matter that we split the code into a couple of sub-queries. Thanks to lazy evalutation of LINQ to SQL, this should be executed as a single query.

I don't know if it shorter but you can also try this version to see if it works better with your server. I don't know exactly how these two answers turn into SQL statements. One might be better based on your indexs and such.
var terms =
from t in Terminations
group t by new {t.Month, t.Year} into g
select new {g.Key, Count = g.Count()};
var hires =
from p in Persons
group p by new {p.Month, p.Year} into g
select new {g.Key, Count = g.Count()};
var summary =
from t in terms
join h in hires on t.Key equals h.Key
select new {t.Key.Month, t.Key.Year,
Hires = h.Count, Terms = t.Count};