I am trying to convert the following query into a LINQ statement.
select u.code, u.id, count(d.unitid) from Unit u
Left join Package d on u.id= d.unitid and d.sstatus = 'Open'
where d.hunit is not null
group by u.code, u.id
This is what I have,
var result =
from U in Table<Unit>().ToList()
join D in Table<Package>().Where(x => x.status == "Open").ToList() on U.Id equals D.UnitId into def1
from def2 in def1.DefaultIfEmpty()
group def2 by new
{
U.Id,
U.code
} into grouped
select new
{
Hmy = grouped.Key.Id,
Code = grouped.Key.Code,
TotalPAckages = grouped.Count()
};
But, in above code, I am also getting the results with UnitId is null in Package table.
I am not sure where and how to apply the Where clause part (where d.hunit is not null) in the above LINQ statement.
Related
I need to convert the following query in SQL to LINQ using the method syntax, but I'm getting confused when I try to include the inline query, joins and groupings:
SELECT CL.*, CB.*, CD.*, CC.*, CS.*
FROM clients AS CL
INNER JOIN (
SELECT A.client_id, SUM(A.amount) AS balance
FROM accounts AS A
WHERE A.account_id = 1
GROUP BY A.client_id
HAVING (SUM(A.amount) > 0.015) OR (SUM(A.amount) < -0.015)
) AS CB ON CL.client_id = CB.client_id
INNER JOIN client_details AS CD ON (CL.client_id = CD.client_id) AND (CL.audit_id = CD.audit_id)
LEFT JOIN client_categories AS CC ON CD.client_category_id = CC.client_category_id
LEFT JOIN statuses AS CS ON CD.status_id = CS.status_id
I did get the GROUP BY and HAVING portions working independently of the overall query, but I have not been able to merge this with the rest as an inline query (though I've tried .Any and other LINQ methods):
.Where(a => a.AccountId == 1)
.GroupBy(a => new { a.ClientId })
.Where(ag => ag.Sum(a => a.Amount) > 0.015M || ag.Sum(a => a.Amount) < -0.015M)
.Select(ag => new { Id = ag.Key.ClientId, Balance = ag.Sum(a => a.Amount) })
I have managed to convert it to LINQ using the query syntax, which works perfectly for me, but I need it in the method (Lambda) syntax:
var clients = from c in _context.Clients
join cb in (from a in _context.Accounts
where a.AccountId == 1
group a by new { Id = a.ClientId } into g
where g.Sum(gs => gs.Amount) > 0.015M || g.Sum(gs => gs.Amount) < -0.015M
select new { g.Key.Id, Balance = g.Sum(gs => gs.Amount) }) on c.Id equals cb.Id
join cd in _context.ClientDetails on new { c.Id, c.AuditId } equals new { cd.Id, cd.AuditId }
join cc in _context.ClientCategories on cd.ClientCategoryId equals cc.Id into ccj
from cc in ccj.DefaultIfEmpty()
join cs in _context.Statuses on cd.StatusId equals cs.Id into csj
from cs in csj.DefaultIfEmpty()
select new Client(c, cb.Balance, new ClientDetails(cd, cc, cs));
Any help greatly appreciated.
It appears that LinqPad offers the solution. Run the LINQ query syntax against your database and, when it finishes, click the Lambda symbol at the bottom of the page to see the method syntax:
LinqPad Window
Thanks LinqPad!
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
};
I am trying to translate the following query with self join to a LINQ expression.
select r2.* from depends d
join request r on d.DESC =r.DESC
join request r2 on d.ID=r2.ID
and d.TYPE ='sometype'
where r.ID= 12345
How can I correct the following LINQ query to match the correct SQL query above?
var result = (from d in depends
join r in request on d.DESC equals r.DESC
join r2 in request on d.ID == r2.ID && d.TYPE == incomingType.ToString()
where r.ID == incomingId
select r2).AsEnumerable();
Why don't you simple use a Where clause if your incomingType is fixed?
Also there is syntax for multiple join conditions, as shown here: LINQ Joining in C# with multiple conditions
E.g.:
var result = (from d in depends
where d.TYPE == incomingType.ToString()
join r in request on
new { ID = r.ID, desc = r.DESC }
equals
new { ID = d.ID, desc = d.DESC }
where r.ID == incomingId
select r).AsEnumerable();
If your incomingType is not actually fixed, and it gets its value from the depends table, you can just add a third parameter to the join condition, e.g.
var result = (from d in depends
where d.TYPE == incomingType.ToString()
join r in request on
new { ID = r.ID, desc = r.DESC, type = r.someType1 }
equals
new { ID = d.ID, desc = d.DESC, type = d.someType2 }
where r.ID == incomingId
select r).AsEnumerable();
I'm using the following query and am having trouble figuring out how to add a join into it:
var chi = Lnq.attlnks.Where(a => a.ownerid == emSysid)
.Select(c => new { sysid });
How can I join this to the "attach" table (ON attlnks.sysid = attach.sysid) and select "name" where sysid is the row id?
For joins in Linq the query expression form is typically more readable than lambda syntax - I believe this is what you are asking for:
var chi = from t in Lnq.attach
join a in Lnq.attlnks
on t.sysid equals a.sysid
where a.ownerid == emSysid
select t.name;
If there is only a single entry that should match at most, you can chain a FirstOrDefault() in this case (or other alternatives like SingleOrDefault, Single, First etc.):
var chi = (from t in Lnq.attach
join a in Lnq.attlnks
on t.sysid equals a.sysid
where a.ownerid == emSysid
select t.name).FirstOrDefault();
If I understood your problem, this should work fine:
var query = from a in attlinks
join aa in attach on a.sysid equals aa.sysid into a2
where a2.sysid == a2.ownerid
select a2.Name;
I am trying to convert a SQL query to a LINQ to entities query, but am having some problems with the LINQ select block.
Here is the SQL query which performs as expected:
SELECT distinct( p.PendingID,
p.Description,
p.Date,
f.Status,
u.UserName,
m.MapID
FROM Pending p
JOIN Users u
ON p.UserID = u.UserID
LEFT JOIN Forks f
ON p.PendingID = f.PendingID
LEFT JOIN Maps m
ON f.ForkID = m.ForkID
ORDER BY p.Date DESC
Here is the LINQ to entities query as I have it thus far:
var pList = (from pending in pendingItems
// JOIN
from user in userList.Where(u => pending.UserID == u.UserID)
// LEFT OUTER JOIN
from fork in forkList.Where(f => pending.ID == f.PendingID)
.DefaultIfEmpty()
// LEFT OUTER JOIN
from map in mapList.Where(m => fork.ID == m.ForkID)
.DefaultIfEmpty()
orderby pending.Date descending
select new
{
ItemID = pending.ID, // Guid
Description = pending.Description, // String
Date = pending.Date, // DateTime
Status = fork.Status, // Int32 (*ERROR HERE*)
UserName = user.UserName, // String
MapID = map.ID // Guid (*ERROR HERE*)
})
.Distinct()
.ToList();
The LINQ query fails on either of the following 2 lines, which attempt to assign values retrieved from left outer join results. If the following lines are omitted, the LINQ query completes without errors:
Status = fork.Status,
MapID = map.ID
Why are those 2 property assignments failing within the LINQ query's select block?
The problem is that due to your outer joins, fork and map may be null. Of course when they're null, you can't access their properties. You may need something like this:
Status = (fork == null) ? null : fork.Status,
MapID = (map == null) ? null : map.ID