We Keep Coding

Linq to sql join with multiple "OR" filters

I need to implement this in Linq-to-sql
SELECT DISTINCT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s ON c.Room = s.Entry_Bar_Code
OR c.HomeRoom = s.Entry_Bar_Code
WHERE s.id = 1021645
All the research I've done on this says that linq-to-sql can't support an "OR" multiple join, and the suggestions are to instead do two joins like this:
SELECT DISTINCT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s ON c.Room = s.Entry_Bar_Code
LEFT OUTER JOIN dbo.Lab_Space s2 ON c.HomeRoom = s2.Entry_Bar_Code
WHERE s.id = 1021645
Those aren't actually the same query though as they'll return different results. Short of just putting the raw SQL into my C# program at this point, is there any way to accomplish the above?

Let's start from beginning. If you use WHERE with column from OUTER JOIN table it means that your query:
SELECT DISTINCT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s ON c.Room = s.Entry_Bar_Code
OR c.HomeRoom = s.Entry_Bar_Code
WHERE s.id = 1021645
is logically equivalent to:
SELECT DISTINCT c.*
FROM dbo.Collector_Capital_Equipment c
JOIN dbo.Lab_Space s
ON c.Room = s.Entry_Bar_Code
OR c.HomeRoom = s.Entry_Bar_Code
WHERE s.id = 1021645;
And this could be achieved with CROSS JOIN(pseudocode):
var q = from c in Collector_Capital_Equipment
from s in Lab_Space
where s.id == 1021645
&& (s.Entry_Bar_Code == c.Room || c.HomeRoom == s.Entry_Bar_Code)
select ...
I assume that you really want to generate query:
SELECT DISTINCT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s
ON (c.Room = s.Entry_Bar_Code OR c.HomeRoom = s.Entry_Bar_Code)
AND s.id = 1021645
which could be represented as:
SELECT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s
ON c.Room = s.Entry_Bar_Code AND s.id = 1021645
INTERSECT
SELECT c.*
FROM dbo.Collector_Capital_Equipment c
LEFT OUTER JOIN dbo.Lab_Space s
ON c.HomeRoom = s.Entry_Bar_Code AND s.id = 1021645
And above query could be achieved with LINQ using set operators.
db<>fiddle demo

I don't think I've ever seen someone use an OR clause on a join before. Does MS SQL Server even support that in SQL?
I'd probably just split this off into two queries, to be honest.
SELECT entry_bar_code
FROM dbo.Lab_Space WHERE id = 1021645;
With the result from that being fed into
SELECT DISTINCT *
FROM dbo.Collector_Capital_Equipment
WHERE c.room == <barcode> OR c.homeRoom == <barcode>

Linq left join returns inner join

I am trying to perform an outer join in C# using Linq, the person mentoring me keeps saying I shouldn't try to do an outer join which isn't really an answer.
What I got from the other threads is that I need the .DefaultIfEmpty() where ever I may not have a record.
I tried it first on just the lines where there may be a missing information then added it to every line just to see if that was the problem.
Every time I run this I get only the inner join records. It works great other than it is not including the two records from my DB that only have information in the first two tables.
var sqlQuery =
from s in ctx.Suppliers
from sp in ctx.SupplierParts
.Where(sp => sp.SupplierID == s.SupplierID)
.DefaultIfEmpty()
from sm in ctx.SupplierManufacturerRelations
.Where(sm => sm.SupplierPNID == sp.SupplierPNID)
.DefaultIfEmpty()
from mp in ctx.ManufacturerParts
.Where(mp => mp.MfgPNID.Equals(sm.MfgPNID))
.DefaultIfEmpty()
from m in ctx.Manufacturers
.Where(m => m.ManufacturerID.Equals(mp.ManufacturerID))
.DefaultIfEmpty()
from im in ctx.ItemMasters
.Where(im => im.PreID == mp.PreID)
.Where(im => im.PartNumber == mp.PartNumber)
.DefaultIfEmpty()
from c in ctx.ComponentClasses
.Where(c => c.CCID == im.CCID)
.DefaultIfEmpty()
from um in ctx.UnitsOfMeasures
.Where(um => um.UOMID == sp.UOMID)
.DefaultIfEmpty()
select new
{ my variables}
var querylist = sqlQuery.Where(n => n.SupplierID == thisSupplier).ToList();
I also tried
from s in ctx.Suppliers
join sp in ctx.SupplierParts on s.SupplierID equals sp.SupplierID
join sm in ctx.SupplierManufacturerRelations on sp.SupplierPNID equals sm.SupplierPNID into spartgroup
from sm in spartgroup.DefaultIfEmpty()
join mp in ctx.ManufacturerParts on sm.MfgPNID equals mp.MfgPNID into mpartgroup
from mp in mpartgroup.DefaultIfEmpty()
join m in ctx.Manufacturers on mp.ManufacturerID equals m.ManufacturerID into mgroup
from m in mgroup.DefaultIfEmpty()
join im in ctx.ItemMasters
on new { key1 = (int)mp.PreID, key2 = (int)mp.PartNumber }
equals new { key1 = im.PreID, key2 = im.PartNumber }
into tpartgroup
from im in tpartgroup.DefaultIfEmpty()
join c in ctx.ComponentClasses on im.CCID equals c.CCID into fullgroup
from c in fullgroup.DefaultIfEmpty()
join um in ctx.UnitsOfMeasures on sp.UOMID equals um.UOMID
This SQL query works and doesn't omit the rows
SELECT Supplier.SupplierID
, SupplierPart.SupplierPNID
, SupplierPart.SupplierPN
, SupplierPart.Description
, SupplierManufacturerRelation.MfgPNID
, ManufacturerPart.PreID
, ManufacturerPart.PartNumber
, ItemMaster.CCID
, ItemMaster.Description AS Expr1
FROM Supplier
Inner JOIN SupplierPart
ON Supplier.SupplierID = SupplierPart.SupplierID
Left JOIN SupplierManufacturerRelation
ON SupplierPart.SupplierPNID = SupplierManufacturerRelation.SupplierPNID
Left JOIN ManufacturerPart
ON SupplierManufacturerRelation.MfgPNID = ManufacturerPart.MfgPNID
Left JOIN ItemMaster
ON ManufacturerPart.PreID = ItemMaster.PreID
AND ManufacturerPart.PartNumber = ItemMaster.PartNumber
WHERE Supplier.SupplierID = 9

For translating SQL to LINQ query comprehension:
Translate FROM subselects as separately declared variables.
Translate each clause in LINQ clause order, translating monadic operators (DISTINCT, TOP, etc) into functions applied to the whole LINQ query.
Use table aliases as range variables. Use column aliases as anonymous type field names.
Use anonymous types (new { ... }) for multiple columns.
Left Join is simulated by using a into join_variable and doing another from from the join variable followed by .DefaultIfEmpty().
Replace COALESCE with the conditional operator and a null test.
Translate IN to .Contains() and NOT IN to !...Contains()
SELECT * must be replaced with select range_variable or for joins, an anonymous object containing all the range variables.
SELECT fields must be replaced with select new { ... } creating an anonymous object with all the desired fields or expressions.
Proper FULL OUTER JOIN must be handled with an extension method.
So from your SQL, your query should look like:
var ans = from s in ctx.Suppliers
join sp in ctx.SupplierParts on s.SupplierID equals sp.SupplierID
join sm in ctx.SupplierManufacturerRelations on sp.SupplierPNID equals sm.SupplierPNID into smj
from sm in smj.DefaultIfEmpty()
join mp in ctx.ManufacturerParts on sm?.MfgPNID equals mp.MfgPNID into mpj
from mp in mpj.DefaultIfEmpty()
join im in ctx.ItemMasters on new { key1 = (int)mp.PreID, key2 = (int)mp.PartNumber } equals new { key1 = im.PreID, key2 = im.PartNumber } into imj
from im in imj.DefaultIfEmpty()
select new {
s.SupplierID, sp.SupplierPNID, sp.SupplierPN, sp.Description, sm.MfgPNID, mp.PreID, mp.PartNumber, im.CCID, Expr1 = im.Description
};

convert SQL to LINQ not working

I want to convert this SQL code to LINQ. Here is my SQL code:
SELECT Rooms.RoomName AS RoomNo, Beds.BedName AS Beds, Rooms.RoomType, ISNULL(CheckIn.CheckIntatus,'') AS Status
FROM CheckIn
INNER JOIN GuestBeds ON CheckIn.GuestBedId = GuestBeds.Id
AND (CheckIn.CheckInStatus = 1 OR CheckIn.CheckIntatus = 2 OR CheckIn.CheckSIntatus = 3)
RIGHT JOIN Beds ON GuestBeds.BedId = Beds.Id
INNER JOIN Rooms ON Beds.RoomId = Rooms.Id
LEFT JOIN Guests ON CheckIn.GuestId = Guests.Id
WHERE Beds.Active = 1 AND Rooms.Active = 1
ORDER BY RoomName, Beds
It works well which means it shows all the RoomName with CheckInStatus. If the Room is not presence in CheckIn table, ot will return the status as Null.
So I want to convert the code to LINQ. SO here is my LINQ code:
from b in Beds
join w in Rooms on b.RoomsId equals w.Id
where (a.CheckInStatus == 3 || a.CheckInStatus == 1 || a.CheckInStatus == 2)
join p in GuestBeds on b.Id equals p.BedId
join a in CheckIn on p.Id equals a.GuestBedId
join t in Guests on a.GuestId equals t.Id
where b.Active == true && w.Active == true
orderby w.RoomName
select new
{
RoomName = w.RoomName,
BedName = b.BedName,
Status = a.CheckInStatus
}
It didnt worked like the first code. It only show the data which contain CheckInStatus. I want it to show all the RoomName inside Room database

Normally I would post some rules for converting SQL to LINQ but this is complicated enough I think I'd need to make new rules. I commented out the references to Guests because as a LEFT JOIN it has no bearing on the answer.
Pull out the WHERE on individual tables and make them sub-queries:
var ActiveBeds = Beds.Where(b => b.Active == 1);
var ActiveRooms = Rooms.Where(r => r.Active == 1);
In LINQ, a RIGHT JOIN must be done by flipping the join to be a left join, so we will create the two sides as sub-queries.
Left side of RIGHT JOIN:
Translate the JOIN conditions that aren't part of an equi-join into a LINQ where clause on the appropriate tables (alternately this could be a subquery as above). The LEFT JOIN becomes a LINQ join/from ... DefaultIfEmpty() phrase, but as noted above isn't needed.
var CheckInsGuestBedsGuests = from c in CheckIn
where (c.CheckInStatus == 1 || c.CheckInStatus == 2 || c.CheckInStatus == 3)
join gb in GuestBeds on c.GuestBedId equals gb.Id
//join g in Guests on c.GuestId equals g.Id into gj
//from g in gj.DefaultIfEmpty()
select new { c, gb /*, g */ };
Right side of RIGHT JOIN:
The other side of the RIGHT JOIN includes an INNER JOIN so put them together in a sub-query:
var ActiveBedsRooms = from b in ActiveBeds
join r in ActiveRooms on b.RoomId equals r.Id
select new { b, r };
Finally, flip the sub-queries to create a left join using the same idiom as above:
var ans = from br in ActiveBedsRooms
join cgbg in CheckInsGuestBedsGuests on br.b.Id equals cgbg.gb.BedId into cgbgj
from cgbg in cgbgj.DefaultIfEmpty()
select new {
RoomNo = br.r.RoomName,
Beds = br.b.BedName,
br.r.RoomType,
Status = cgbg.c.CheckInStatus
};
NOTE: If you were not using LINQ to SQL, the Status expression would fail when cgbg is null and you would need
Status = cgbg?.c.CheckInStatus
but unfortunately LINQ to SQL/EF doesn't handle the null conditional operators yet.
BTW, nice query - brings back memories of when I used to write hotel front desk software :)

SQL to LINQ (to implement LEFT JOIN)

I have one below SQL query, it is more complex having some GroupBy, Conditions, etc. which i skip here in post to make my question easy:
SELECT
SUBSTRING(TSL.ctg_name, 6, 100) AS 'TREKK', *
FROM Filteredctg_timbersettlementline AS TSL
INNER JOIN Filteredctg_timbersettlement AS TS
ON TSL.ctg_timbersettlementid = TS.ctg_timbersettlementid
LEFT JOIN FilteredNew_property AS P
ON TS.ctg_propertyid = P.new_propertyid
WHERE (TS.ctg_timbersettlementid = #TimberSettlementID) AND
(TSL.ctg_reportgroup = 'TREKK')
I tried below Linq:
var Trekks = (from ts in XrmContext.ctg_timbersettlementSet
join tsl in XrmContext.ctg_timbersettlementlineSet
on ts.Id equals tsl.ctg_timbersettlementid.Id
join p in XrmContext.New_propertySet
on ts.ctg_propertyid.Id equals p.New_propertyId
into temp
from p in temp.DefaultIfEmpty()
where ts.ctg_timbersettlementId == TimberSettlementGuid
where tsl.ctg_reportgroup == "TREKK"
select new
{
tsl.ctg_name,
ts.ctg_BasisAllocatedForestryFund,
}).ToList();
It throwing me an error:
The method 'GroupJoin' cannot follow the method 'Join' or is not supported. Try writing the query in terms of supported methods or call the 'AsEnumerable' or 'ToList' method before calling unsupported methods.
How can i achive LEFT JOIN?

To achieve a left join, you need to use an intermediary DefaultIfEmpty() :
var query = from c in db.Customers
join o in db.Orders
on c.CustomerID equals o.CustomerID into sr
from x in sr.DefaultIfEmpty()
select new {
CustomerID= c.CustomerID, ContactName=c.ContactName,
OrderID = x.OrderID == null ? -1 : x.OrderID};

c# linq not equals variation

I have a linq query w/ entity frameworks that works and gets the needed information, but now i am having trouble doing the opposite.
Currently it gets all the data that is needed using the joins to link tables but i need to to get some data that is not match some of the joins.
I know you can only use "equals" om linq, but i need info that is not equals
i.e. join ec in c.IsoNe on ap.idLook not equals ec.idAll
Below is the working code, but not how i need it now. any help would be appreciated...
var test = (from bil in bilats
join ap in c.Allegro on bil.idAll equals ap.idAll
join ec in c.IsoNe on ap.idLook equals ec.idAll
join cb in c.Comp on ap.idCompBuy equals cb.idComp
join cs in c.Com on ap.idCompSell equals cs.idComp
join iby in c.IsoNe on cb.idComp equals iby.idComp
join iss in c.IsoNe on cs.idComp equals isl.idComp
orderby bil.HBegin ascending
where bil.HBegin >= ec.DateTStart
where bil.HBegin < ec.DateTEnd
select new
{
Cont = ec.ContractID,
ContType = ap.idScheduleType,
Sel = isel.ISONE1,
Buy = ibel.ISONE,
HBegin = bil.HBegin,
}).ToList();

As far as I know, you'll have to create a Cartesian product and then use a where-condition to filter it. (I'm making the perhaps rash assumption that you want an inner join rather than a left join, but an inner join is what the join keyword represents.) Something like this:
var test = (from bil in bilats
join ap in c.Allegro on bil.idAll equals ap.idAll
from ec in c.IsoNe where ap.idLook != ec.idAll
join cb in c.Comp on ap.idCompBuy equals cb.idComp
join cs in c.Com on ap.idCompSell equals cs.idComp
join iby in c.IsoNe on cb.idComp equals iby.idComp
join iss in c.IsoNe on cs.idComp equals isl.idComp
orderby bil.HBegin ascending
where bil.HBegin >= ec.DateTStart
where bil.HBegin < ec.DateTEnd
select new
{
Cont = ec.ContractID,
ContType = ap.idScheduleType,
Sel = isel.ISONE1,
Buy = ibel.ISONE,
HBegin = bil.HBegin,
}).ToList();

Sounds like a join might be the wrong approach. Have a look at unions or subqueries
C# linq union question
how to do subquery in LINQ