Not counting null values from a linq LEFT OUTER JOIN query - c#

I have this sql query that does exactly what i want but i need it in linq. It returns a few AVC rows and counts how many PersonAVCPermission that has status 1 linked to it
SELECT a.Id, a.Name, a.Address, COUNT(p.AVCID) AS Count
FROM AVC AS a
LEFT OUTER JOIN
(
SELECT PersonAVCPermission.AVCId
FROM PersonAVCPermission
WHERE PersonAVCPermission.Status = 1
) AS p
ON a.Id = p.AVCId
GROUP BY a.Id, a.Name, a.Address
I have this query in linq and it does the same thing except when there are no PersonAVCPermission it still counts 1
var yellows = odc.PersonAVCPermissions.Where(o => o.Status == (int)AVCStatus.Yellow);
var q = from a in odc.AVCs
from p in yellows.Where(o => o.AVCId == a.Id).DefaultIfEmpty()
group a by new { a.Id, a.Name, a.Address } into agroup
select new AVCListItem
{
Id = agroup.Key.Id,
Name = agroup.Key.Name,
Address = agroup.Key.Address,
Count = agroup.Count(o => o.Id != null)
};
Im guessing that with DefaultIfEmpty() it places null rows in the list that then gets counted so i try to exclude them with (o => o.Id != null) but it still counts everything as at least one
If i dont use DefaultIfEmpty() it skips the rows with count 0 completely
How can i exclude them or am i doing it completely wrong?

How about using .Any() and a Let?
var yellows = odc.PersonAVCPermissions.Where(o => o.Status == (int)AVCStatus.Yellow);
var q = from a in odc.AVCs
let Y = (from p in yellows.Where(o => o.AVCId == a.Id) select p).Any()
where Y == true
group a by new { a.Id, a.Name, a.Address } into agroup
select new AVCListItem
{
Id = agroup.Key.Id,
Name = agroup.Key.Name,
Address = agroup.Key.Address,
Count = agroup.Count(o => o.Id != null)
};

You don't need the join, nor the grouping:
var q = from a in odc.AVCs
select new AVCListItem
{
Id = a.Id,
Name = a.Name,
Address = a.Address,
Count = yellows.Where(o => o.AVCId == a.Id).Count()
};

Related

LINQ GroupBy a name, but how to get Id of users?

I want to display how many transfers did every customer.
I want to display CustomerId, Name and Totaly amount of transfers.
I mean I want to display CustomerId too, not only Name and Amount transfers.
Everything works fine except CustomerId: it is empty in my DataGridview.
I don't know how to do and I would really appreciate any kind of help.
Here is my code:
using (Db db = new Db())
{
var statistic = (from u in db.Transfers
join c in db.Customers on u.CustomerId equals c.CustomerId
where u.IsActive == true && u.Paid == true
group u by c.FirstName into g
select new
{
// here I get Headertext but not Id's value
Id = g.Select(x =>x.CustomerId),
Name = g.Key,
Totaly = g.Sum(x => x.Amount)
}).OrderByDescending(x => x.Totaly).ToList();
if (statistic != null)
{
dgvCustomerList.DataSource = statistic;
}
}
The correct way is to group it by CustomerId (because CustomerId is unique, you will get distinct customers inside select and then you can use FirstOrDefault() for getting FirstName property):
using (Db db = new Db())
{
var statistic = (from u in db.Transfers
join c in db.Customers on u.CustomerId equals c.CustomerId
where u.IsActive == true && u.Paid == true
group u by c.CustomerId into g
select new
{
Id = g.Key, // here I get Headertext but not Id's value
Name = g.FirstOrDefault().FirstName,
Totaly = g.Sum(x => x.Amount)
}).OrderByDescending(x => x.Totaly).ToList();
if (statistic != null)
{
dgvCustomerList.DataSource = statistic;
}
}
You can group by both customerId and FirstName
using (Db db = new Db())
{
var statistic = (from u in db.Transfers
join c in db.Customers on u.CustomerId equals c.CustomerId
where u.IsActive == true && u.Paid == true
group u by new {key c.FirstName,key c.CustumerId} into g
select new
{
Id = g.Key.CustumerId,//g.Select(x =>x.CustomerId), // here I get Headertext but not Id's value
Name = g.Key.FirstName,
Totaly = g.Sum(x => x.Amount)
}).OrderByDescending(x => x.Totaly).ToList();
if (statistic != null)
{
dgvCustomerList.DataSource = statistic;
}
}

Linq Queries - How to join the below two group by queries? On Course ID

I'm trying to join two group by queries to get one results set.
var query = from PP in _db.paymentPlans
join APP in _db.Applications on PP.applicationID equals APP.ApplicationId
join C in _db.Courses on APP.courseID equals C.courseID
where PP.active == true && APP.agentID == agentID
orderby C.courseID ascending
group new {C,PP} by new {C.courseID} into totalRecievable
// Query 1
from PD in _db.paymentDetails
join PP in _db.paymentPlans on PD.paymentPlanID equals PP.paymentPlanID
join APP in _db.Applications on PP.applicationID equals APP.ApplicationId
join C in _db.Courses on APP.courseID equals C.courseID
where PP.active == true && APP.agentID == agentID
orderby C.courseID ascending
group new { C,PD } by new { C.courseID, C.cricosCode, C.courseName } into paymentsCourseWise
// Query 2
select new PdPpAppCourseModel
{
courseID = paymentsCourseWise.Key.courseID,
cricosCode = paymentsCourseWise.Key.cricosCode,
courseName = paymentsCourseWise.Key.courseName,
totalAmount = totalRecievable.Sum(x => x.PP.totalAmount),
paidAmount = paymentsCourseWise.Sum(x => x.PD.paidAmount)
}).ToList();
Total about is taken from query 1 as it should group in payment plan(PP) level.
You can only combine enumerations of the same type, you could project both to a common class and then concatenate them:
var result1 = db1.table.Where(a=>a.value>0).Select( x=> new Foo() { //set props });
var result2 = db2.table.Where(a=>a.value>0).Select( x=> new Foo() { //set props });
var resultSum = result1.Concat(result2);
Similarly you can apply this in your code and join this two groups.

Error in Linq query when join multiple table

My linq query is:
var query1 = (from grp in ctnx.tblGroupDatas
group grp by grp.MeterID_FK into g
let maxId = g.Max(gId => gId.GroupDataID)
select new { metId = g.Key, maxId });
query2 = (from met in ctnx.tblMet
from mod in ctnx.tblMod.Where(mo => mo.ModID == met.Mod_FK).DefaultIfEmpty()
from grp in ctnx.tblGroupDatas.Where(gr => gr.Met_FK == met.MetID)
from group1 in db.tblMetRelateGroups.Where(x => x.Met_FK == met.MetID)
from q1 in query1.Where(q => q.metId == met.MetID && grp.GroupDataID == q.maxId)
where (group1.GroupMetID_FK == groupID)
select new
{
met.MetID,
mod.ModSerial,
met.MetSerial,
met.MetWaterSharingNo,
met.MetPowerSharingNo,
grp.GroupDate,
grp.GroupDataID
});
var gridobisdata = query2.OrderByDescending(m => m.GroupDate);
but this show error:
The specified LINQ expression contains references to queries that are
associated with different contexts.

join with multiple group by element and select extra columns

Can you please help to convert this from sql to linq, i am new to linq and been trying this and couldn't succeed. Let me know if this is even possible or not?
SELECT max(Products.ProductID) as ProductID, Products.SKU, Products.Name, Products.RRP, Products.Price,
max(Products.FrontTall) as FrontTall,
ProductsCategory.SortOrder,
Products.ColorValue,
max(Products.ColorImg) as ColorImg,
Products.IsPrimary,
Products.Visible
FROM Products INNER JOIN ProductsCategory ON Products.ProductID = ProductsCategory.ProductID
WHERE (ProductsCategory.CategoryID = 5 ) AND (Products.Visible = 1) AND (Products.Inactive = 0) AND (Products.Deleted = 0 or Products.Deleted is null)
GROUP BY SKU, Products.Name, RRP, Price, ColorValue, ProductsCategory.SortOrder, IsPrimary, Visible
AND this is what i am trying
var products = (from p in db.Products
join cp in db.ProductsCategories on p.ProductID equals cp.ProductID
where cp.CategoryID == catId && p.Visible == true && p.Inactive == false && (p.Deleted == null || p.Deleted == false)
group p by new {
p.SKU,
p.Name,
p.RRP,
p.Price,
p.ColorValue,
p.IsPrimary,
p.Visible,
cp.SortOrder
} into grouped
select new {
ProductID,
FrontTall,
ColorImg,
SKU = grouped.Key.SKU,
Name = grouped.Key.Name,
RRP = grouped.Key.RRP,
Price = grouped.Key.Price,
ColorValue = grouped.Key.ColorValue,
IsPrimary = grouped.Key.IsPrimary,
Visible = grouped.Key.Visible,
SortOrder = grouped.Key.SortOrder
})
.OrderBy(x => x.SortOrder);
I need to get the ProductID, FrontTall and ColorImg field value without including in group by
Thanks in advance.
Kish
select new {ProductID = grouped.Max(x => x.ProductID)}

linq after groupby unable to get column values

I am getting data from multiple tables by joining and i want to group data on particular column value but after group by statement i can access my aliases and their properties. What mistake i am making?
public List<PatientHistory> GetPatientHistory(long prid)
{
using(var db = new bc_limsEntities())
{
List<PatientHistory> result =
(from r in db.dc_tresult
join t in db.dc_tp_test on r.testid equals t.TestId into x
from t in x.DefaultIfEmpty()
join a in db.dc_tp_attributes on r.attributeid equals a.AttributeId into y
from a in y.DefaultIfEmpty()
where r.prid == prid
group new {r,t,a} by new {r.testid} into g
select new PatientHistory
{
resultid = r.resultid,
bookingid = r.bookingid,
testid = r.testid,
prid = r.prid,
attributeid = r.attributeid,
result = r.result,
Test_Name = t.Test_Name,
Attribute_Name = a.Attribute_Name,
enteredon = r.enteredon,
Attribute_Type = a.Attribute_Type
}).ToList();
return result;
}
}
You're doing this wrong way. As been said by Jon after grouping the sequences with aliases r,t,a doesn't exist. After grouping you receive the sequence g with sequances of r,t,a in each element of g. If you want get one object from each group (for example most recent) you should try this:
List<PatientHistory> result =
(from r in db.dc_tresult
join t in db.dc_tp_test on r.testid equals t.TestId into x
from t in x.DefaultIfEmpty()
join a in db.dc_tp_attributes on r.attributeid equals a.AttributeId into y
from a in y.DefaultIfEmpty()
where r.prid == prid
group new {r,t,a} by new {r.testid} into g
select new PatientHistory
{
resultid = g.Select(x => x.r.resultid).Last(), // if you expect single value get it with Single()
// .... here add the rest properties
Attribute_Type = g.Select(x => x.a.Attribute_Type).Last()
}).ToList();
I appreciated this question so I thought I would add another potential usage case. I would like feedback on what the cleanest approach is to getting table information through a group operation so that I can project later in the select operation. I ended up combining what the OP did which is to pass objects into his group clause and then used the g.Select approach suggested by YD1m to get table information out later. I have a LEFT JOIN so I'm defending against nulls :
// SQL Query
//DECLARE #idCamp as Integer = 1
//
//select *,
//(select
//count(idActivityMaster)
//FROM tbActivityMasters
//WHERE dftidActivityCategory = A.idActivityCategory) as masterCount
//FROM tbactivitycategories A
//WHERE idcamp = #idCamp
//ORDER BY CategoryName
int idCamp = 1;
var desiredResult =
(from c in tbActivityCategories
.Where(w => w.idCamp == idCamp)
from m in tbActivityMasters
.Where(m => m.dftidActivityCategory == c.idActivityCategory)
.DefaultIfEmpty() // LEFT OUTER JOIN
where c.idCamp == idCamp
group new {c, m} by new { m.dftidActivityCategory } into g
select new
{
idActivityCategory = g.Select(x => x.m == null ? 0 : x.m.dftidActivityCategory).First(),
idCamp = g.Select(x => x.c.idCamp).First(),
CategoryName = g.Select(x => x.c.CategoryName).First(),
CategoryDescription = g.Select(x => x.c.CategoryDescription).First(),
masterCount = g.Count(x => x.m != null)
}).OrderBy(o=> o.idActivityCategory);
desiredResult.Dump("desiredResult");
If I just use a basic group approach I get the results but not the extra column information. At least I can't find it once I group.
var simpleGroup = (from c in tbActivityCategories
.Where(w => w.idCamp == idCamp)
.OrderBy(o => o.CategoryName)
from m in tbActivityMasters
.Where(m => m.dftidActivityCategory == c.idActivityCategory)
.DefaultIfEmpty() // LEFT OUTER JOIN
where c.idCamp == idCamp
group m by m == null ? 0 : m.dftidActivityCategory into g
select new
{
// How do I best get the extra desired column information from other tables that I had before grouping
// but still have the benefit of the grouping?
// idActivityCategory = g.Select(x => x.m == null ? 0 : x.m.dftidActivityCategory).First(),
// idCamp = g.Select(x => x.c.idCamp).First(),
// CategoryName = g.Select(x => x.c.CategoryName).First(),
// CategoryDescription = g.Select(x => x.c.CategoryDescription).First(),
// masterCount = g.Count(x => x.m != null)
idActivityCategory = g.Key,
masterCount = g.Count(x => x != null)
});
simpleGroup.Dump("simpleGroup");
Please tear this up. I'm trying to learn and it just seems like I'm missing the big picture here. Thanks.
UPDATE : Cleaned up by moving the work into the group and making the select more straight forward. If I had known this yesterday then this would have been my original answer to the OP question.
int idCamp = 1;
var desiredResult =
(from c in tbActivityCategories
.Where(w => w.idCamp == idCamp)
from m in tbActivityMasters
.Where(m => m.dftidActivityCategory == c.idActivityCategory)
.DefaultIfEmpty() // LEFT OUTER JOIN
where c.idCamp == idCamp
group new { c, m } by new
{ idActivityCategory = m == null ? 0 : m.dftidActivityCategory,
idCamp = c.idCamp,
CateGoryName = c.CategoryName,
CategoryDescription = c.CategoryDescription
} into g
select new
{
idActivityCategory = g.Key.idActivityCategory,
idCamp = g.Key.idCamp,
CategoryName = g.Key.CateGoryName,
CategoryDescription = g.Key.CategoryDescription,
masterCount = g.Count(x => x.m != null)
}).OrderBy(o => o.idActivityCategory);
desiredResult.Dump("desiredResult");

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