Convert sql query to EF - sql

Can anybody please help with this SQL query to transform it to EF Linq Expression?
select MI.Id, B.Count, B.Cost, Name, Price, Unity, I.Count, I.Cost, BOL.Date, BOL.type, BOL.Number
from Balance B inner join MaterialsInfo MI on Mi.Id = B.MaterialsId
inner join Income I on MI.Id = I.MaterialsId
inner join BillOfLading BOL on I.BillOfLadingId = BOL.Id
where B.Id in (select Id from (select max(Date), Id from Balance group by Balance.MaterialsId))
and I.Id in (select Id from(select max(Date), Income.Id as Id from Income inner join BillOfLading BOL on Income.BillOfLadingId = BOL.Id group by Income.MaterialsId))
I've been trying to do this for days, so I could really use some help.
Do you need extra info?
Thank you in advance.
Edit
Here is a little part of the diagram, maybe it helps

It seems the subqueries in both of your conditions in where clause is incorrect. Because your
group by column is missing in the select statement
And it is very unclear what you trying to achieve from the subqueries.
Without a clear understanding of your subqueries, all I can prepare for you is this.
var result = await (from balance in yourDBContect.Balances
join material in yourDBContect.MaterialsInfos on balance.MaterialsId equals material.Id
join income in yourDBContect.Incomes on material.Id equals income.MaterialsId
join bill in yourDBContect.BillOfLadings on income.BillOfLadingId equals bill.Id
where Balances.GroupBy(g => g.MaterialsId)
.Select(s => new
{
MaterialsId = s.Key,
MaxDate = s.Max(x => x.Date)
}).ToList().Contains(new { balance.MaterialsId, MaxDate = balance.Date })
&& Incomes.Join(BillOfLadings,
p => p.BillOfLadingId,
e => e.Id,
(p, e) => new { p, e })
.GroupBy(g => g.p.MaterialsId)
.Select(s => new
{
MaterialsId = s.Key,
MaxDate = s.Max(s => s.e.Date)
}).ToList().Contains(new { income.MaterialsId, MaxDate = balance.Date })
select new
{
material.Id,
balance.Count,
balance.Cost,
balance.Name,
balance.Price,
balance.Unity,
ICount = income.Count,
ICost = income.Cost,
bill.Date,
bill.Type,
bill.Number
});
Notes:
Alias for Income.Count and Income.Cost are changed because an object cannot contain exactly same nenter code hereamed property.
Linq for a proper subquery will replace new List<int>().

Related

Linq to SQL - Query with multiple joins, sum, grouping, having

I have the following query that I would like to translate to linq.
SELECT
SUM(Credits.CreditAmount)
,Transactions.Id
,Person.FullName
,Person.Id
FROM
Person
JOIN
Transactions
ON Person.AccountId = Transactions.AccountId
JOIN Credits
ON Transactions.Id = Credits.TransactionId
WHERE
Person.Type = 'AccountHolder'
AND Person.Status = 'Active'
AND Transactions.CancelledDate IS NULL
AND Credits.CancelledDate IS NULL
GROUP BY Transactions.AccountId, Person.FullName, Person.Id
HAVING SUM(Credits.CreditAmount) > 20
This is what I came up with. It's an absolute pig... The SQL it generates must be awful.
var query = from p in Person
join t in Transactions
on p.AccountId equalas t.AccountId
join c in Credits
on t.TransactionId = c.TransactionId
where p.Status == "Active" &&
p.Type = "AccountHolder" &&
t.CancelledDate == null &&
c.CancelledDate == null
group new { c.CreditAmount, t.AccountId, p.FullName, p.Id } by new { t.AccountId, p.FullName, p.SSN } into grp
let sumC = grp.Select(x => x.CreditAmount).Sum()
select new
{
TotalCredit = sumC,
AccountId = grp.Key.AccountId,
FullName = grp.Key.FullName,
Id = grp.Key.Id
};
query.Where(p => p.TotalServiceCredit > 20);
The SQL query runs in approximately 3 seconds but I have yet to find the patience to let the Linq query finish. I was wondering if there is something different I should be doing to accomplish this "group, sum, having" query I'm trying to write? Is there something I can do to help Linq generate more performat SQL?
UPDATE
Turns out sgmoore had the right idea. The key to the performance issue was in his answer.
The difference between this
let sumC = grp.Select(x => x.CreditAmount).Sum()
and this
TotalCredit = grp.Sum(x => x.CreditAmount)
was the difference between a query that finishes and one that does not.
See my revised LINQ query below which completes in about the same time as the SQL (5.3 seconds for SQL vs 5.6 seconds for LINQ).
var query = from p in Person
join t in Transactions
on p.AccountId equalas t.AccountId
join c in Credits
on t.TransactionId = c.TransactionId
where p.Status == "Active" &&
p.Type = "AccountHolder" &&
t.CancelledDate == null &&
c.CancelledDate == null
group new { c.CreditAmount, t.AccountId, p.FullName, p.Id } by new { t.AccountId, p.FullName, p.SSN } into grp
select new
{
TotalCredit = grp.Sum(x => x.CreditAmount),
AccountId = grp.Key.AccountId,
FullName = grp.Key.FullName,
Id = grp.Key.Id
};
query.Where(p => p.TotalServiceCredit > 20);
Thanks for all your help!
I don't disagree with WEI_DBA's comment but if you need to do this, then you might find it easier to break this into several queries, eg
var query1 = from p in Person
join t in Transactions on p.AccountId equals t.AccountId
join c in Credits on t.TransactionId equals c.TransactionId
where p.Status == "Active" &&
p.Type = "AccountHolder" &&
t.CancelledDate == null &&
c.CancelledDate == null
select new { c.CreditAmount, t.AccountID, p.FullName, p.Id};
var query2 = (from p in query1
group p by new { p.AccountId, p.FullName, p.Id } into grp
select new
{
TotalCredit = grp.Sum(x => x.CreditAmount),
AccountId = grp.Key.AccountId,
FullName = grp.Key.FullName,
Id = grp.Key.Id
};
var query3 = (from p in query2 where p.TotalCredit > 20 select p);
Then you can let LINQ combine this into one sql command.
As always, it is a good idea to check and verify the actual TSQL generated.

SQL Query to LINQ Lambda expression

I am trying to convert a bit of SQL containing a LEFT OUTER JOIN with a GROUP BY clause into a LINQ Lambda expression.
The SQL I need to convert is:-
SELECT m.MemberExternalPK
FROM Member.Member AS m LEFT OUTER JOIN Member.Account AS a ON m.MemberID = a.MemberID
GROUP BY MemberExternalPK
HAVING COUNT(AccountID) = 0
I have managed to get it working correctly with an INNER JOIN between Member and Accounts like this (for a count of Account = 1) but this does not work for Accounts with a count of 0 (hence the LEFT OUTER JOIN is required):-
Members.Join(Accounts, m => m.MemberID, a => a.MemberID, (m, a) => new {m, a})
.GroupBy(t => t.m.MemberExternalPK, t => t.a)
.Where(grp => grp.Count(p => p.AccountID != null) == 1)
.Select(grp => grp.Key)
I have been trying to experiment with the .DefaultIfEmpty() keyword but have so far been unsuccessful. Any help would be greatly appreciated :)
I think this is what you're after:
Query syntax
var members = new List<Member>
{
new Member {MemberId = 1, MemberExternalPk = 100},
new Member {MemberId = 2, MemberExternalPk = 200}
};
var accounts = new List<Account>
{
new Account {AccountId = 1, MemberId = 1}
};
var query =
from m in members
join a in accounts on m.MemberId equals a.MemberId into ma
from ma2 in ma.DefaultIfEmpty()
where ma2 == null
group ma2 by m.MemberExternalPk into grouped
select new {grouped.Key};
The result of this example is that only the number 200 is returned. As it will only return the MemberExternalPk for members that don't have an account. i.e. As MemberId 2 doesn't have a related Account object, it is not included in the reuslts.
var list = members.GroupJoin(accounts,m=>m.MemberId, a => a.MemberId,
(m,a) => new {m,a})
.Where(x=>x.a.Count()==0)
.Select(s=>s.m.MemberExternalPk);

Left outter join linq

How do i change the training events into a left outer join in training events im very basic at linq so excuse my ignorance its not retrieve records that don't have any trainnevent reference attached to it
var q = from need in pamsEntities.EmployeeLearningNeeds
join Employee e in pamsEntities.Employees on need.EmployeeId equals e.emp_no
join tevent in pamsEntities.TrainingEvents on need.TrainingEventId equals tevent.RecordId
where need.EmployeeId == employeeId
where need.TargetDate >= startdate
where need.TargetDate <= enddate
orderby need.TargetDat
It's best to use where in combination with DefaultIfEmpty.
See here: LEFT JOIN in LINQ to entities?
var query2 = (
from users in Repo.T_Benutzer
from mappings in Repo.T_Benutzer_Benutzergruppen.Where(mapping => mapping.BEBG_BE == users.BE_ID).DefaultIfEmpty()
from groups in Repo.T_Benutzergruppen.Where(gruppe => gruppe.ID == mappings.BEBG_BG).DefaultIfEmpty()
//where users.BE_Name.Contains(keyword)
// //|| mappings.BEBG_BE.Equals(666)
//|| mappings.BEBG_BE == 666
//|| groups.Name.Contains(keyword)
select new
{
UserId = users.BE_ID
,UserName = users.BE_User
,UserGroupId = mappings.BEBG_BG
,GroupName = groups.Name
}
);
var xy = (query2).ToList();
Which is equivalent to this select statement:
SELECT
T_Benutzer.BE_User
,T_Benutzer_Benutzergruppen.BEBG_BE
-- etc.
FROM T_Benutzer
LEFT JOIN T_Benutzer_Benutzergruppen
ON T_Benutzer_Benutzergruppen.BEBG_BE = T_Benutzer.BE_ID
LEFT JOIN T_Benutzergruppen
ON T_Benutzergruppen.ID = T_Benutzer_Benutzergruppen.BEBG_BG

I need help re-writing a SQL query into LINQ format

I'm not good with LINQ yet and could use some help with the syntax.
Thanks!
The below query needs to be written in LINQ for C#.
SELECT Galleries.GalleryTitle, Media.*
FROM Galleries
INNER JOIN Media ON Galleries.GalleryID = Media.GalleryID
WHERE (Galleries.GalleryID = 150)
ORDER BY MediaDate DESC, MediaID DESC
Or with query syntax:
var query = from g in db.Galleries
join m in db.Media on g.GalleryID equals m.GalleryID
where g.GalleryID == 150
orderby m.MediaDate descending, m.MediaID descending
select new { g.GalleryTitle, Media = m };
Something like this:
var query = db.Galleries
.Join(db.Media, g => g.GalleryID, m => m.GalleryID, (g, m) => new {g, m})
.Where(r.g.GalleryID == 150)
.Select(res => new {res.g.GalleryTitle, Media = res.m}
.OrderByDescending(o => o.Media.MediaDate)
.ThenByDescending(o => o.Media.MediaID);

JOIN and LEFT JOIN equivalent in LINQ with Method Syntax

I am converting a SQL query to LINQ that creates a left join with 1-to-1 mapping, and it has to be in Method Syntax. I have been pulling off my hair trying to accomplish this to no veil. I can do it in Lambda Syntax. Below is the example query I am trying to run. They are not actual code. Would someone point out what I am doing wrong?
SQL:
SELECT item.*, item_status.*
FROM item
LEFT JOIN item_status
ON item.ID = item_status.itemID
AND item_status.FLAGGED = true
WHERE item.published_date > "2008-06-19"
LINQ:
var linq_query = (
from selected_item in item
join selected_item_status in item_status
on selected_item.ID equals item_status.itemID into joined
from item_status in joined.DefaultIfEmpty()
where item_status.FLAGGED = true
select new {selected_item, selected_item_status}).ToList();
The join ... into becomes a GroupJoin and the second from becomes a SelectMany:
var linq_query = Item
.GroupJoin(
item_status.Where(x => x.selected_item_status.FLAGGED), // EDIT: Where clause moved here.
selected_item => selected_item.ID,
selected_item_status => selected_item_status.itemID,
(selected_item, joined) => new
{
selected_item,
statuses = joined.DefaultWithEmpty(),
})
.SelectMany(x => x.statuses.Select(selected_item_status => new
{
x.selected_item,
selected_item_status,
}))
// EDIT: Removed where clause.
.ToList();
It looks like the Where makes the left outer join unnecessary, as null statuses will be filtered out anyway.
EDIT: No, upon reviewing the SQL it looks like your LINQ query is slightly incorrect. It should be:
var linq_query = (
from selected_item in item
join selected_item_status
in (
from status in item_status
where status.FLAGGED
select status)
on selected_item.ID equals item_status.itemID into joined
from item_status in joined.DefaultIfEmpty()
select new {selected_item, selected_item_status}).ToList();