Develop Reference

How to get the group sum in my complex linq query

below I have listed a linq query that works properly in my asp.net.mvc web app.
In addition I would like to group over 'allowance.ParameterId' in order to get the group sum for 'allowance.Freight (instead of multiple records for the given key).
var query = from ara in aras
join company in companies on ara.Id equals company.ARAId
join wasteWater in wasteWaters on company.Id equals wasteWater.CompanyId
join allowance in allowances on wasteWater.Id equals allowance.WasteWaterID
join parameter in parameters on allowance.ParameterId equals parameter.Id into JoinedParameterAllowance
from parameter in JoinedParameterAllowance.DefaultIfEmpty()
where company.Activ == true && company.End == null && company.Template == false
&& wasteWater.End == null
select new FreightSummaryViewModel
{
AraName = ara.Name,
AraId = ara.Id,
AllowedParameter = parameter.Name,
AllowedFreight = allowance.Freight
};
I have tried to insert 'group ...' but failed to get it right.
Could someone help me please to set up the proper syntax?
Thank you in advance, Manu

I have little idea about relations in your database, so I improvised...
// Some dummy data to play with
var aras = Enumerable.Range(0, 5).Select(i => new { Id = i, Name = "Ara" + i });
var companies = Enumerable.Range(0, 15).Select(i => new { Id = i, ARAId = i % 5, Activ = true, End = (DateTime?)null, Template = false });
var wasteWaters = Enumerable.Range(0, 35).Select(i => new { Id = i, CompanyId = i / 15, End = (DateTime?)null });
var allowances = Enumerable.Range(0, 70).Select(i => new { Id = i, WasteWaterID = i, ParameterId = i % 4, Freight = i * 1000 });
var parameters = Enumerable.Range(0, 4).Select(i => new { Id = i, Name = "Parameter" + i });
And this is what I believe you looked for:
var query =
from ara in aras
join company in companies on ara.Id equals company.ARAId
join wasteWater in wasteWaters on company.Id equals wasteWater.CompanyId
join allowance in allowances on wasteWater.Id equals allowance.WasteWaterID
join parameter in parameters on allowance.ParameterId equals parameter.Id
into JoinedParameterAllowance
// from parameter in JoinedParameterAllowance.DefaultIfEmpty()
where true
&& company.Activ == true
&& company.End == null
&& company.Template == false
&& wasteWater.End == null
group allowance by new
{
AraName = ara.Name,
AraId = ara.Id,
ParameterId = allowance.ParameterId
} into myGroup
select new //FreightSummaryViewModel
{
AraName = myGroup.Key.AraName,
AraId = myGroup.Key.AraId,
AllowedParameter = myGroup.Key.ParameterId,
AllowedFreight = myGroup.Sum(g => g.Freight)
};

LINQ JOIN and OUTER JOIN - How to turn SQL into LINQ expression

I would like to turn the following SQL query into a LINQ expression (using Entity Framework 6.1). Thus far I have been unable find an acceptable LINQ expression that produces similar results. Any help turning this simple SQL statement into a LINQ express would be appreciated.
SELECT AAG.Id AS GroupId,
A.Id AS ActivityId,
A.Title As Title,
CASE WHEN AA.CompletedOn IS NULL THEN CAST(1 AS bit) ELSE CAST(0 AS bit) END AS Completed,
COALESCE(AAG.PointValue, 0) + SUM(COALESCE(AQ.PointValue, 0)) AS PointTotal
FROM ActivityAssignmentGroup AAG
INNER JOIN ActivityAssignment AA ON AA.GroupId = AAG.Id
INNER JOIN Activity A ON AA.ActivityId = A.Id
LEFT OUTER JOIN ActivityQuestion AQ ON AQ.ActivityId = A.Id
WHERE AAG.AssignedToId = 6
GROUP BY AAG.Id, A.Id, A.Title, CASE WHEN AA.CompletedOn IS NULL THEN CAST(1 AS bit) ELSE CAST(0 AS bit) END, COALESCE(AAG.PointValue,0)
Without the LEFT OUTER JOIN portion, the below LINQ statement is partially complete, but I cannot figure out the appropriate syntax to add the LEFT OUTER JOIN condition:
var assignments = await (from g in db.AssignmentGroups.AsNoTracking().Where(x => x.AssignedToId == studentTask.Result.PersonId)
join aa in db.ActivityAssignments.AsNoTracking() on g.Id equals aa.GroupId
join a in db.Activities.AsNoTracking() on aa.ActivityId equals a.Id
select new ActivityListViewModel
{
Id = a.Id,
Points = g.PointValue ?? 0,
Title = a.Title,
GroupId = g.Id,
Complete = (aa.CompletedOn != null)
});
Edit:
Thanks for the response Bob. I attempted to use the DefaultIfEmpty and looked at the resultant SQL query generated by the Entity Framework, but it didn't work. Prior to making this post, this is the LINQ statement I attempted:
var assignments = from g in db.AssignmentGroups.AsNoTracking().Where(x => x.AssignedToId == studentTask.Result.PersonId)
join aa in db.ActivityAssignments.AsNoTracking() on g.Id equals aa.GroupId
join a in db.Activities.AsNoTracking() on aa.ActivityId equals a.Id
from aq in db.ActivityQuestions.Where(q => q.ActivityId == a.Id).DefaultIfEmpty()
group aq by new { ActivityId = aq.ActivityId, Title = a.Title, GroupId = g.Id, Points = g.PointValue ?? 0, Completed = (aa.CompletedOn != null) } into s
select new ActivityListViewModel
{
Id = s.Key.ActivityId,
Points = s.Key.Points + s.Sum(y => y.PointValue ?? 0), //g.PointValue ?? 0,
Title = s.Key.Title,
GroupId = s.Key.GroupId,
Complete = s.Key.Completed
};
Of course, it didn't work either. The result was items missing the Id (ActivityId).

You need DefaultIfEmpty() to convert a join to left outer join, documentition from MSDN here
var assignments = await (from g in db.AssignmentGroups.AsNoTracking().Where(x => x.AssignedToId == studentTask.Result.PersonId)
join aa in db.ActivityAssignments.AsNoTracking() on g.Id equals aa.GroupId
join a1 in db.Activities.AsNoTracking() on aa.ActivityId equals a1.Id into a2
from a in a2.DefaultIfEmpty()
select new ActivityListViewModel
{
Id = a == null ? null : a.Id,
Points = g.PointValue ?? 0,
Title = a == null ? null : a.Title,
GroupId = g.Id,
Complete = (aa.CompletedOn != null)
});

Just to close the loop (and thank you Bob Vale)... the query below works:
var assignments = from g in db.AssignmentGroups.AsNoTracking().Where(x => x.AssignedToId == studentTask.Result.PersonId)
join aa in db.ActivityAssignments.AsNoTracking() on g.Id equals aa.GroupId
join a in db.Activities.AsNoTracking() on aa.ActivityId equals a.Id
from aq in db.ActivityQuestions.Where(q => q.ActivityId == a.Id).DefaultIfEmpty()
group aq by new { ActivityId = a.Id, Title = a.Title, GroupId = g.Id, Points = g.PointValue ?? 0, Completed = (aa.CompletedOn != null) } into s
select new ActivityListViewModel
{
Id = s.Key.ActivityId,
Points = s.Key.Points + s.Sum(y => y.PointValue ?? 0), //g.PointValue ?? 0,
Title = s.Key.Title,
GroupId = s.Key.GroupId,
Complete = s.Key.Completed
};
The issue was the group by condition and using ag.ActivityId when I should have used a.Id.

How to check if column is exist in Linq join query c#?

Hi I am running one Linq query to join three tables. below is the query...
answerText = ds.Tables[0];
questionAvg = ds.Tables[1];
interviews = ds.Tables[2];
var data = from at in answerText.AsEnumerable()
join qa in questionAvg.AsEnumerable() on at.Field<int>("ID") equals qa.Field<int>("DealerID")
join inter in interviews.AsEnumerable() on at.Field<int>("ID") equals inter.Field<int>("DealerID")
select new
{
DealerID = at.Field<int>("ID"),
DealerName = at.Field<string>("Name"),
AnswerText1 = at.Field<int?>("12"),
AnswerText2 = at.Field<int?>("8"),
AnswerText3 = at.Field<int?>("4"),
AnswerText4 = at.Field<int?>("0"),
AnswerText5 = at.Field<int?>("-4"),
Rank = qa.Field<Int64?>("Rank"),
Average = qa.Field<decimal?>("Average"),
N = inter.Field<int?>("N")
};
now sometimes answerText datatable will only have column 12 and 8.., so it is missing columns 4 0 -4. how should i avoid that column check in above query and just provide 0 there.

I'm not 100% sure what you're asking about, but I assumed you need AnswerText properties to be int not int?. And they should be set to 0 when item is not present. You can use ?? operator:
var data = from at in answerText.AsEnumerable()
join qa in questionAvg.AsEnumerable() on at.Field<int>("ID") equals qa.Field<int>("DealerID")
join inter in interviews.AsEnumerable() on at.Field<int>("ID") equals inter.Field<int>("DealerID")
select new
{
DealerID = at.Field<int>("ID"),
DealerName = at.Field<string>("Name"),
AnswerText1 = at.Field<int?>("12") ?? 0,
AnswerText2 = at.Field<int?>("8") ?? 0,
AnswerText3 = at.Field<int?>("4") ?? 0,
AnswerText4 = at.Field<int?>("0") ?? 0,
AnswerText5 = at.Field<int?>("-4") ?? 0,
Rank = qa.Field<Int64?>("Rank"),
Average = qa.Field<decimal?>("Average"),
N = inter.Field<int?>("N")
};

How to write Outer Join using LINQ

I am using the below Inner Join to retrive the Data between the two tables, but all data is not getting populated. I tried implementing Outer join by connecting using CCY1== CCY1 and PCODE == PCODE, but no luck.
var q = from g1 in TableCCY1.AsEnumerable()
join g2 in TableCCY2.AsEnumerable()
on g1.Field<string>("CCY1") equals g2.Field<string>("CCY1")
where g1.Field<string>("PCODE") == g2.Field<string>("PCODE")
select new
{
g1currency = g1.Field<string>("CCY1"),
g2currency = g2.Field<string>("CCY1"),
g1code = g1.Field<string>("PCODE"),
g2code = g2.Field<string>("PCODE"),
g1Amt1 = g1.Field<string>("AMT1"),
g2Amt2 = g2.Field<string>("AMT2")
};
Thanks for your help.

For left join you can use this approuch: http://msdn.microsoft.com/en-us/library/vstudio/bb397895.aspx
The code should be:
var q = from g1 in TableCCY1
join g2 in TableCCY2 on g1.CCY1 equals g2.CCY1 && g1.PCODE equals g2.PCODE into TableCCY3
from g3 in TableCCY3.DefaultIfEmpty()
select new
{
g1currency = g1.CCY1,
g2currency = (g3 == null ? String.Empty : g3.CCY1),
g1code = g1.PCODE,
g2code = (g3 == null ? String.Empty : g3.PCODE),
g1Amt1 = g1.AMT1,
g2Amt2 = (g3 == null ? 0 : g3.AMT2)
};

It looks like you just want to union/concat the two tables into one and then just group on those two columns. You're not logically joining the two tables. That actually makes it much easier.
var q = from row in TableCCY1.AsEnumerable().Concat(TableCCY2.AsEnumerable())
group row by new
{
CCY1 = row.Field<string>("CCY1"),
PCode = row.Field<string>("PCODE")
} into matches
select new
{
CCY1 = matches.Key.CCY1,
PCODE = matches.Key.PCode,
Sum = matches.Sum(match => match.Field<decimal?>("AMT2")),
};

Entity Framework - Results from subquery, speed issue?

I've made a query to get a list of articles, each bound to a "header",
so i retrieve the header plus the related articles and their properties.
The query works, however in its current style it is
Somewhat messy ( in my opinion)
The .ToList() takes way longer than i would expect.
Does anyone see any obvious reason for the speed-issue?
var offerheaders =
from o in dbcontext.F_CAB_OFFER_HEADERS
where
o.OFHD_FK_BUYER == userinfo.orgaTypeSequence
&& o.OFHD_VALID_FROM <= userinfo.selectedDate
&& o.OFHD_VALID_TO >= userinfo.selectedDate
&& o.OFHD_DELETED_YN == 0
&& o.OFHD_DELETED_BY_OWNER_YN == false
&& o.OFHD_OFFER_TYPE == userinfo.offerType
orderby o.OFHD_NO ascending
select o;
var offerlist =
from ofhd in offerheaders
select new {
ofhd = new {
OfferNo = ofhd.OFHD_NO,
OfferSequence = ofhd.OFHD_SEQUENCE,
ValidFrom = ofhd.OFHD_VALID_FROM,
ValidTo = ofhd.OFHD_VALID_TO,
OfferType = ofhd.OFHD_OFFER_TYPE,
Maingroup = new { cdmg_seq = ofhd.F_CAB_CD_MAIN_GROUP_TYPE.CDMG_SEQUENCE, Desc = ofhd.F_CAB_CD_MAIN_GROUP_TYPE.CDMG_DESC },
Supplier = new {
Name = ofhd.F_CAB_GROWER.F_CAB_ORGANISATION.ORGA_NAME,
Pic = ofhd.F_CAB_GROWER.F_CAB_ORGANISATION.ORGA_FK_PICTURE,
Seq = ofhd.F_CAB_GROWER.GROW_SEQUENCE
},
Caption = ofhd.OFHD_CAPTION,
Seperate = ofhd.OFHD_SHOW_SEPARATE_YN,
//ofdts = (from ofdt in dbcontext.F_CAB_OFFER_DETAILS.Where(x => x.OFDT_FK_OFFER_HEADER == ofhd.OFHD_SEQUENCE && x.OFDT_NUM_OF_ITEMS > 0 && x.OFDT_LATEST_DELIVERY_DATE_TIME > compareDateTime && x.OFDT_LATEST_ORDER_DATE_TIME > compareDateTime)
ofdts = from ofdt in dbcontext.F_CAB_OFFER_DETAILS
join props in dbcontext.F_CAB_CAB_PROP on ofdt.OFDT_FK_CAB_CODE equals props.PROP_FK_CABC_SEQ
join cabcode in dbcontext.F_CAB_CD_CAB_CODE on ofdt.OFDT_FK_CAB_CODE equals cabcode.CABC_SEQUENCE
join cabgroup in dbcontext.F_CAB_CD_CAB_GROUP on cabcode.CABC_FK_CAB_GROUP equals cabgroup.CDGR_SEQUENCE
join grouptype in dbcontext.F_CAB_CD_GROUP_TYPE on cabgroup.CDGR_FK_GROUP_TYPE equals grouptype.CDGT_SEQUENCE
join maingrouptype in dbcontext.F_CAB_CD_MAIN_GROUP_TYPE on grouptype.CDGT_FK_MAIN_GROUP equals maingrouptype.CDMG_SEQUENCE
join caca in dbcontext.F_CAB_CAB_CASK_MATRIX on ofdt.OFDT_FK_CACA_SEQ equals caca.CACA_SEQUENCE
join cask in dbcontext.F_CAB_CD_CASK on caca.CACA_FK_CASK equals cask.CDCA_SEQUENCE
join vbncode in dbcontext.F_CAB_CAB_VBN_MATRIX on cabcode.CABC_SEQUENCE equals vbncode.CVMA_FK_CAB_CODE
join grel in dbcontext.F_CAB_GENERAL_RELATIONS on ofdt.OFDT_FK_GREL_SEQ equals grel.GREL_SEQUENCE into greltable
from g_loj in greltable.DefaultIfEmpty()
where
ofdt.OFDT_FK_OFFER_HEADER == ofhd.OFHD_SEQUENCE
&& ofdt.OFDT_NUM_OF_ITEMS > 0
&& props.PROP_FK_CDLA_SEQ == userinfo.lang.CDLA_SEQUENCE
orderby props.PROP_CAB_DESC ascending
select new {
Desc = props.PROP_CAB_DESC,
Group = new { cdgr_seq = cabgroup.CDGR_SEQUENCE, Desc = cabgroup.CDGR_DESC },
Grouptype = new { grouptype.CDGT_SEQUENCE, Desc = grouptype.CDGT_DESC },
Properties = new CABProperties { props = props },
Price = ofdt.OFDT_ITEM_PRICE,
PIC_SEQ = ofdt.OFDT_FK_PICTURE ?? ((cabcode.CABC_FK_PICTURE ?? cabcode.CABC_SEQUENCE)),
PIC_URL = ofdt.OFDT_EXT_PICTURE_REF ?? "",
Seq = ofdt.OFDT_SEQUENCE,
Available = ofdt.OFDT_NUM_OF_ITEMS,
CabCode = ofdt.F_CAB_CD_CAB_CODE.CABC_CAB_CODE,
VBNCode = vbncode.CVMA_FK_VBN_CODE,
Remark = ofdt.OFDT_REMARK,
IsSpecial = ofdt.OFDT_SPECIAL_YN,
Arrived = inTransit ? ofdt.OFDT_ARRIVAL_DATE < DateTime.Now : true,
Cask = new CABCask { cask = cask, caca = caca },
Supplier = g_loj == null ? (ofdt.OFDT_SUPPLIER ?? "") : g_loj.GREL_NAME,
SupplierWeb = g_loj == null ? "" : g_loj.GREL_WEBSITE_URL,
SupplierLogo = g_loj == null ? ofhd.F_CAB_GROWER.F_CAB_ORGANISATION.ORGA_FK_PICTURE : g_loj.GREL_FK_PICT_SEQ,
SupplierSeq = g_loj == null ? -1 : g_loj.GREL_SEQUENCE,
}
}
};
userinfo.mainofferlist = offerlist.ToList();

As Daniel Kelly also mentioned the ToList function is where your query is executed, because these LinqToEntities queries are executed at the point where they are first enumerated, and ToList does that to be able to create a list.
Basically the reason why your querying takes so much time can be separated into two different reasons:
you are using too much projections and I thine (the parts with new {
})
your query has an incredible amount of join clauses
I would recommend to separate your query into subqueries, and run them separately like the first part in
...
select o
use
...
select o).ToList()
by breaking down the main query where you have a lot of subqueries it will be faster and much more readable, so you have less "messiness".
And last but not least you should create mapping for the anonymous objects, and use those classes other than projection that should speed up your query.