I have a list x with anonymous types in which i want to use a value which pre-calculated
int count1 =
(from users in dc.BeadSets
where users.UserId == i
select users
).Count();
var x =
(from users in dc.Users
where users.Id == i
select new { username = users.UserName
, fullname = users.FirstName + " " + users.LastName
, userid = users.Id
}
).ToList();
Now this is working fine as usual
Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>'
to 'System.Collections.Generic.List<AnonymousType#2>'
but while i am trying to use like this its throwing above error
int count1 =
(from users in dc.BeadSets
where users.UserId == i
select users
).Count();
x =
(from users in dc.Users
where users.Id == i
select new { beadsets= count1
, username = users.UserName
, fullname = users.FirstName + " " + users.LastName
, userid = users.Id }
).ToList();
Related
A user can perform actions based on an occurrence value. When this value is equal to 'DAILY', I would like to retrieve all daily actions that have not been completed the last 24 hours.
The working SQL query:
SELECT distinct a.* FROM action as a LEFT OUTER JOIN history as h
ON a.id = h.action_id
AND h.user_id= <user> WHERE a.occurrence = 'DAILY' AND (h.id is NULL OR h.entry_date < TIMESTAMP 'yesterday')
The equivalent native query:
#Query(value =
"SELECT distinct a.* FROM action a "
+ "LEFT OUTER JOIN history h "
+ "ON a.id = h.action_id "
+ "AND h.user_id = :userId "
+ "WHERE a.occurrence='DAILY' AND (h.id IS NULL OR h.entry_date < :yesterday) ", nativeQuery = true)
public List<Action> findAllAvailableActions(#Param("userId") Long userId, #Param("yesterday") ZonedDateTime yesterday);
How it is called in my service :
ZonedDateTime today = ZonedDateTime.now(ZoneOffset.UTC);
ZonedDateTime yesterday = today.minus(1,ChronoUnit.DAYS);
Long userId = userDTO.getId();
List<Action> result = actionRepositoryCustom.findAllAvailableActions(userId, yesterday);
However, I do get the wrong results in my tests (actions that have already been completed are returned). I am afraid this is linked to the date parameter. The attribute entry_date is declared as ZoneDateTime in my entity. What am I doing wrong ?
hibernate : 5.2.4
You can't pass a ZonedDateTime into a native SQL query. You need to convert it to Calendar:
#Query(value =
"SELECT distinct a.* FROM action a "
+ "LEFT OUTER JOIN history h "
+ "ON a.id = h.action_id "
+ "AND h.user_id = :userId "
+ "WHERE a.occurrence='DAILY' AND (h.id IS NULL OR h.entry_date < :yesterday)", nativeQuery = true)
public List<Action> findAllAvailableActions(#Param("userId") Long userId, #Param("yesterday") Calendar yesterday);
And you can convert your ZonedDateTime this way:
public Calendar convertToDatabaseColumn(ZonedDateTime entityAttribute) {
if (entityAttribute == null) {
return null;
}
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(entityAttribute.toInstant().toEpochMilli());
calendar.setTimeZone(TimeZone.getTimeZone(entityAttribute.getZone()));
return calendar;
}
This approach is described here: link
I am sql query us producing correct result, but when i'm doing the same in LINQ. Output is incorrect. Please let me know where my making mistake.
Following linq query that i created.
LINQ Query:
List<UserModel> Model = (from users in db.UserM
join ct in db.CustT on users.UserId equals ct.UserID into group1
from g1 in group1.DefaultIfEmpty()
join ti in db.TestIn on g1.TestId equals ti.TestID into group2
from g2 in group2.DefaultIfEmpty()
where (users.CustomerId==CustomerId) && (users.RoleId == 4) && (users.Status == 1)
group new
{
g2.TestInvitationID,
g2.TestID,
}
by new
{
users.FirstName,
users.CreatedOn,
users.Email,
users.UserId
} into group4
select new UserModel
{
Name = group4.Key.FirstName,
CreatedOn = group4.Key.CreatedOn,
EmailId = group4.Key.Email,
UserId = group4.Key.UserId,
NoOfTestTaken = group4.Select(x=>x.TestID).Distinct().Count(),
NoOfInvitationsSent = group4.Count(x => x.TestInvitationID != 0)
}).ToList();
SQL Query:
SELECT IsNull(COUNT(distinct TS.TestId),0) AS NoOfTests,
IsNull(COUNT(TS.TestInvitationID),0) AS NoOfInvitations,
UM.Email,
UM.UserId,
UM.FirstName,
UM.CreatedOn
FROM UserM as UM
left JOIN CustT AS CT
ON UM.UserId=CT.UserId
left JOIN TestIn AS TS
ON TS.TestId = CT.TestId
WHERE UM.CustomerId=41
AND UM.RoleId=4
and UM.[Status]=1
GROUP BY UM.UserId, UM.Email, UM.FirstName, UM.CreatedOn
Tables:
"UserM" - columns: UserId, Email, FirstName, CreatedOn
"CustT" - columns: TestId, UserId,
"TestIn" - columns: TestInvitationId, TestId
The difference between SQL COUNT(expr) and LINQ Count is that the former excludes NULL values, which produces a difference when used on right side of a left outer join with no matching records (SQL will produce 0 while LINQ 1). The closest LINQ equivalent is Count(expr != null).
So the direct translation of your SQL query would be like this (note that the generated SQL query could and most likely will be different):
(A side note: When converting SQL query to LINQ, it's good to use the same aliases to make it easier to see the mappings)
var query =
from um in db.UserMasters
join ct in db.CustTests on um.UserId equals ct.UserID
into ctGroup from ct in ctGroup.DefaultIfEmpty() // left outer join
join ts in db.TestInvitaions on ct.TestId equals ts.TestID
into tsGroup from ts in tsGroup.DefaultIfEmpty() // left outer join
where um.CustomerId == UserSession.CustomerId
&& um.RoleId == 4
&& um.Status == 1
group ts by new { um.UserId, um.Email, um.FirstName, um.CreatedOn } into g
select new UserModel
{
Name = g.Key.FirstName,
CreatedOn = g.Key.CreatedOn,
EmailId = g.Key.Email,
UserId = g.Key.UserId,
NoOfTestTaken = g.Where(ts => ts != null).Select(ts => ts.TestID).Distinct().Count(),
NoOfInvitationsSent = g.Count(ts => ts != null)
};
var result = query.ToList();
I suspect that the following row is the problem because is not the same like in your sql:
Linq:
NoOfInvitationsSent = group4.Count(x => x.TestInvitationID != 0)
SQL:
IsNull(COUNT(TS.TestInvitationID),0) AS NoOfInvitations
Due to counting items from a left join Linq should be instead:
NoOfInvitationsSent = group4.Where(i => i != null).Count()
To put it all together, with a bit of better formatting:
var model = (from users in db.UserMasters
join ct in db.CustTests on users.UserId equals ct.UserID into group1
from ct in group1.DefaultIfEmpty()
join ti in db.TestInvitaions on ct.TestId equals ti.TestID into group2
from ct in group2.DefaultIfEmpty()
where users.CustomerId == UserSession.CustomerId &&
users.RoleId == 4 &&
users.Status == 1
group new { ct.TestInvitationID, ct.TestID }
by new
{
users.FirstName,
users.CreatedOn,
users.Email,
users.UserId
} into grouping
select new UserModel
{
Name = grouping.Key.FirstName,
CreatedOn = grouping.Key.CreatedOn,
EmailId = grouping.Key.Email,
UserId = grouping.Key.UserId,
NoOfTestTaken = grouping.Where(i => i != null).Select(x => x.TestID).Distinct().Count(),
NoOfInvitationsSent = grouping.Where(i => i != null).Count()
}).ToList();
I am trying to reproduce a SQL query using a LINQ to Entities query. The following SQL works fine, I just don't see how to do it in LINQ. I have tried for a few hours today but I'm just missing something.
SELECT
h.ReqID,
rs.RoutingSection
FROM ReqHeader h
JOIN ReqRoutings rr ON rr.ReqRoutingID = (SELECT TOP 1 r1.ReqRoutingID
FROM ReqRoutings r1
WHERE r1.ReqID = h.ReqID
ORDER BY r1.ReqRoutingID desc)
JOIN ReqRoutingSections rs ON rs.RoutingSectionID = rr.RoutingSectionID
Edit***
I was able to get this working after looking at other examples including the one provided her by Miki. Here is the code that works for me:
First I created a query called route to hold the top record I needed to join to
var route = (from rr in context.ReqRoutings
where rr.ReqID == id
orderby rr.ID descending
select rr).Take(1);
I was then able to join to my requisitions table and the ReqRoutings lookup table
var header = (from h in context.ReqHeaders
join r in route on h.ID equals r.ReqID
join rs in context.ReqRoutingSections on r.RoutingSectionID equals rs.ID
where h.ID == id
select {ReqID = h.ID,
RoutingSection = rs.RoutingSection}
I am using Northwnd sample database
Customers,Orders,Employees table
Here I am getting top 1 order group by customer and order's employeeid
Please let me know If this is matching with your requirement or not
var ord = from o in NDC.Orders
orderby o.OrderID descending
group o by o.CustomerID into g
select new {CustomerID=g.Key,Order=g.OrderByDescending(s=>s.OrderID).First() };
var res1 = from o in ord
join emp in NDC.Employees
on o.Order.EmployeeID equals emp.EmployeeID into oemp
select new {Order=o.Order,employee=oemp };
Response.Write(res1.ToList().Count);
foreach (var order in res1)
{
Response.Write(order.Order.CustomerID + "," +
order.Order.OrderID + ","+
order.Order.EmployeeID+"<br/>");
}
// Above code is working .I have tried to convert your query to linq and replace your datacontext name with 'NDC'
var ord = from rr in NDC.ReqRoutings
orderby rr.ReqRoutingID descending
group rr by rr.ReqID into g
select new
{
ReqID = g.Key,
ReqRoutings = g.OrderByDescending(s => s.ReqRoutingID).First()
};
var res1 = from o in ord
join emp in NDC.ReqRoutingSections on o.ReqRoutings.RoutingSectionID
equals emp.RoutingSectionID into oemp
select new { ReqRoutings = o.ReqRoutings, employee = oemp };
Response.Write(res1.ToList().Count);
foreach (var order in res1)
{
Response.Write(order.ReqRoutings.ReqID + "," +
order.ReqRoutings.ReqRoutingID + "," +
order.ReqRoutings.RoutingSectionID + "<br/>");
}
Please let know if it is help you or not
Can someone help me converting the following SQL Query into LINQ expression?
select student.StudentID,
student.FirstName + ' ' + student.MiddleInitial + ' ' + student.LastName,
student.OpenDate,
acct.Balance
from Student student
inner join
(Select StudentID, Sum(Amount) as Balance
from Account
Group by StudentID) as acct on student.StudentID = acct.StudentID
The following LINQ expression works! Thank you so much Phil!!!
var results = (from s in Students
join a in Accounts on s.StudentID equals a.StudentID
group a by new
{s.StudentID, s.FirstName, s.MiddleInitial, s.LastName, s.OpenDate}
into z
select new
{ StudentID = z.Key.StudentID,
FirstName = z.Key.FirstName,
MiddleInitial = z.Key.MiddleInitial,
LastName = z.Key.LastName,
OpenDate = z.Key.OpenDate,
Balance = z.Sum(a=> a.Amount)
}
);
Thank you!
Give this a try?
var stu =
from s in db.Students
join a in db.Account on s.StudentID equals a.StudentID
group a by new
{s.StudentID, s.FirstName, s.MiddleInitial, s.LastName, s.OpenDate}
into z
select new
{ StudentID = z.Key.StudentID,
FullName = string.Format("{0} {1} {2}",z.Key.FirstName, z.Key.MiddleInitial, z.Key.LastName),
OpenDate = z.Key.OpenDate,
Balance = z.Sum(a=>a.Amount)
};
Im trying to write query in linq
Select UserId, UserNumber
FROM User
where UserNumber in
(Select UserNumber
FROM User
group by UserNumber
having Count(UserId) = 1)
Aby hints ?
var query = from u in User
group u by u.UserNumber into usergroup
where usergroup.Count() == 1
from item in usergroup
select new { item.UserId,item.UserNumber };
If subqueries are your thing, you could do it this way.
var subquery =
from u in User
group u by u.UserNumber into g
where g.Count() = 1
select g.Key;
var query =
from u in User
where subquery.Any(num => num == u.UserNumber)
select u;