I have the following SQL statement:
CASE
WHEN wt.pmtlr_oi IS NULL OR (SELECT COUNT(*) FROM mc.SCHEDENTRY WITH (NOLOCK) WHERE wt_oi = wt.wtskoi AND shedref_oi NOT IN (SELECT shdoi FROM mc.SCHDULE WITH (NOLOCK) WHERE aenm LIKE '%Breakin%')) = 0 AND wt.pmtlr_oi IS NULL
THEN 'Break-In'
ELSE 'Planned'
END AS schedule
which I have translated into:
Schedule = wt.pmtlr_oi == null || (from sch in SCHEDENTRies where wt_oi == wt.wtskoi && shedref_oi !(from sc in SCHDULEs
where sc.Aenm.Contains("Breakin") select sc.Shdoi)).Count() == 0 && wt.pmtlr_oi == null ? "Break-In" : "Planned"}
Here's how it looks in the select statement:
select new {Schedule = wt.pmtlr_oi == null || (from sch in SCHEDENTRies where wt_oi == wt.wtskoi && shedref_oi !(from sc in SCHDULEs
where sc.Aenm.Contains("Breakin") select sc.Shdoi)).Count() == 0 && wt.pmtlr_oi == null ? "Break-In" : "Planned"});
However when I try and run it there are some problems which I do not know how to fix. The first one is that the compiler doesn't appear to like the NOT IN found here:
&& shedref_oi !(from sc in SCHDULEs
I get a "A query body must end with a select clause or a group clause" error.
The compiler also doesn't like this:
select sc.Shdoi)).Count() == 0
On the outer parenthesis I get a "Syntax error ',' expected" error and on the period I get a "Statement expected" error message.
I would appreciate some help in troubleshooting this.
EDIT:
OK, After the comments I have corrected the LINQ statement to look like this:
select new {Schedule = wt.pmtlr_oi == null || (from sch in SCHEDENTRies where wt_oi == wt.wtskoi && !(from sc in SCHDULEs
where sc.Aenm.Contains("Breakin") select sc.Shdoi).Contains(shedref_oi)).Count() == 0 && wt.pmtlr_oi == null ? "Break-In" : "Planned"});
and the compiler likes it. However, it still doesn't like the .Count(). I get a "Statement expected" error. Am I incorrect in using .Count() for the sql SELECT COUNT(*)?
Related
I always thought LINQ to SQL equivalent for an exists query is to use Any(). But i recently wrote a query in LINQ , which basically is trying to find if duplicate records exists in single table.
Anycontext.Contacts.Any(c => ((c.FirstName == contact.FirstName && c.LastName == contact.LastName && c.AddressLine1 == contact.AddressLine1 && c.Zip == contact.Zip)||
(!String.IsNullOrEmpty(contact.Email) && c.Email == contact.Email)))
matching criteria is simple to find contacts with same FirstName, LastName and AddressLine1 or same Email. This query times out in 30 sec(default), there are just 500K rows in this table.
Wherecontext.Contacts.Where(c => ((c.FirstName == contact.FirstName && c.LastName == contact.LastName && c.AddressLine1 == contact.AddressLine1 && c.Zip == contact.Zip)||
(!String.IsNullOrEmpty(contact.Email) && c.Email == contact.Email))).Count()>0
I was forced to use Where clause and then do count greater than 0 to find if any duplicate exists in the set. What i can not understand is, why LINQ to SQL on simple Any clause timing out.
Any explanation will be really great here.
EDIT
SQL From from LINQ Pad
ANY
SELECT
(CASE
WHEN EXISTS(
SELECT NULL AS [EMPTY]
FROM [Accounts].[Contacts] AS [t0]
WHERE ([t0].[CompanyID] = #p0) AND ((([t0].[FirstName] = #p1) AND ([t0].[LastName] = #p2) AND ([t0].[AddressLine1] = #p3) AND ([t0].[Zip] = #p4)) OR (([t0].[FirstName] = #p5) AND ([t0].[LastName] = #p6) AND (EXISTS(
SELECT NULL AS [EMPTY]
FROM [Accounts].[PhoneNumbers] AS [t1]
WHERE ([t1].[ContactNumber] = #p7) AND ([t1].[ContactID] = [t0].[ContactID])
))))
) THEN 1
ELSE 0
END) AS [value]
Where
SELECT [t0].[ContactID]
,[t0].[CompanyID]
,[t0].[CompanyTitle]
,[t0].[FirstName]
,[t0].[LastName]
,[t0].[AddressLine1]
,[t0].[AddressLine2]
,[t0].[City]
,[t0].[State]
,[t0].[Zip]
,[t0].[Email]
,[t0].[Salutation]
,[t0].[IsActive]
FROM [Accounts].[Contacts] AS [t0]
WHERE ([t0].[CompanyID] = #p0)
AND (
(
([t0].[FirstName] = #p1)
AND ([t0].[LastName] = #p2)
AND ([t0].[AddressLine1] = #p3)
AND ([t0].[Zip] = #p4)
)
OR (
([t0].[FirstName] = #p5)
AND ([t0].[LastName] = #p6)
AND (
EXISTS (
SELECT NULL AS [EMPTY]
FROM [Accounts].[PhoneNumbers] AS [t1]
WHERE ([t1].[ContactNumber] = #p7)
AND ([t1].[ContactID] = [t0].[ContactID])
)
)
)
)
Not completely sure if this is what you want, but you could compare, I'm guessing you wont run the test often, as it would be better to test for existence before you input the data to the DB.
If you want to find the duplicates then
var queryA = from a in db.someTable
select a.value;
foreach(var row in queryA){
Console.Write(queryA.Where(b => b == row).Count() > 1 ? row: "");
}
If you just want to test if it exist then.
var queryA = from a in db.someTable
select a.value;
var queryB = queryA;
queryB.Distinct();
Console.Write(queryB.Count() != queryA.Count() ? "Yes" : "No");
I'm trying to write a correlated subquery in the where clause like this:
var foo = from d in session.Query<Document>()
where true ==
( from a in session.Query<ACLEntry>()
where a.Id == d.Id || a.Id == null
select a.Result
).FirstOrDefault()
select d;
The expected SQL output is very similar to this unanswered question on SO.
I think the Linq statement itself is fine because I can get it to run in LinqPad where I was prototyping. But NHibernate throws me these mysterious errors:
ERROR NHibernate.Hql.Parser [(null)] - NoViableAltException(86#[])
ERROR NHibernate.Hql.Parser [(null)] - MismatchedTreeNodeException(72!=3)
Is this an unsupported scenario with the NHibernate LINQ provider? Any ideas on how I might be able to restructure this query to get around it?
Try this instead :
var foo = from d in session.Query<Document>()
where (from a in session.Query<ACLEntry>()
where a.Id == d.Id || a.Id == null
select a.Result
).FirstOrDefault() != null
select d;
Hope this will help !!
It is probably having some trouble parsing the true == ... portion of the query.
Might want to try this instead,
var foo = from d in session.Query<Document>()
where (from a in session.Query<ACLEntry>()
where a.Id == d.Id || a.Id == null
select a.Result
).FirstOrDefault()
select d;
When I run the following query in SQL Server Management Studio I get 132 rows of data. This is correct.
select *
from cyc.contac con
where (con.note_turn is null) and
(con.cont_type <> '_') and
(con.cont_code <> 'D') and
(con.cont_type <> 'Q')
When I run the following Linq query from my code I get over 11000 records. This is not correct. I am wondering why my linq query is not constraining by the constraints in my where clause.
var query = from contac in context.CONTACs
orderby contac.ID
where (contac.note_turn == null) &&
(contac.cont_type != "_") &&
(contac.cont_code != "D") &&
(contac.cont_type != "Q")
select contac;
i have a problem to build my linq query and i need you help , the following code is what i have got so far
, it does has some errors as expected, so, this is my sql query :
*im new to linq and did searched over google.
select CAST(h.changedate as date) as 'RegDate' ,count (cast(h.changedate as date)) as 'Amount' from T_TalmidStatusHistory h
join T_talmid t on h.talmidid = t.talmidid
where t.talmidStatusID=16 and h.[statusid] != 16
and h.id =
(
select max(id) from T_TalmidStatusHistory
where T_TalmidStatusHistory.talmidid=h.talmidid and T_TalmidStatusHistory.[statusid] != 16
)
group by CAST(h.changedate as date)
and this is what i have right now in linq:
var res = from r in db.T_TalmidStatusHistories
from m in db.T_TalmidStatusHistories
join t in db.T_Talmids on r.TalmidID equals t.TalmidID
where t.TalmidStatusID == 16 && r.StatusID != 16
&& r.id == from l in db.T_TalmidStatusHistories
where m.TalmidID == r.TalmidID && m.StatusID != 16
select new{db.T_TalmidStatusHistories.OrderByDescending(tp => tp.id).FirstOrDefault().id }
group h by h.changedate as date
select new { h.changedate as date, count (cast(h.changedate as date))};
Edit:
i'm expecting to get the number of students that sign up on each date,
my error is :
Operator '==' cannot be applied to operands of type 'int' and 'System.Linq.IQueryable'
at line : r.id == from l in db.T_TalmidStatusHistories
ty.
The whole part
from l in db.T_TalmidStatusHistories ... count (cast(h.changedate as date))}
is one query which is compared to r.id by the == operator.
Change it to
...
r.id == (db.T_TalmidStatusHistories
.Where(m.TalmidID == r.TalmidID && m.StatusID != 16)
.OrderByDescending(tp => tp.id).FirstOrDefault().id)
group h by h.changedate as date
select new { h.changedate as date, count (cast(h.changedate as date))};
I would like this SQL to be converted to LINQ. (it shouldl select rows from input which do not exist in table production based on 3 columns. If a column in both tables contains NULL, it should be considered as having the same value)
SELECT i.* FROM INPUT AS i
WHERE NOT EXISTS
(SELECT p.Agent FROM Production AS p
WHERE ISNULL(i.CustID,'') <> ISNULL(p.CustID,'')
AND ISNULL(i.CustName,'') <> ISNULL(p.CustName,'')
AND ISNULL(i.household,'') <> ISNULL(p.Household,''))
First of all - this is not a good SQL query. Every column is wrapped in a non-sargable function which means that the engine won't be able to take advantage of any indexes on any of those columns (assuming you have any).
Let's start by rewriting this as a semi-decent SQL query:
SELECT i.*
FROM Input i
LEFT JOIN Production p
ON (p.CustID = i.CustID OR (p.CustID IS NULL AND i.CustID IS NULL))
AND (p.CustName = i.CustName OR (p.CustName IS NULL AND i.CustName IS NULL))
AND (p.Household = i.Household OR
(p.Household IS NULL AND i.Household IS NULL))
WHERE p.CustID IS NULL
Now having said this, LEFT JOIN / IS NULL is not great for efficiency either, but we don't have much choice here because we're comparing on multiple columns. Based on your column names, I'm starting to wonder if the schema is properly normalized. A CustID should most likely be associated with one and only one CustName - the fact that you have to compare both of these seems a bit odd. And Household - I'm not sure what that is, but if it's a varchar(x)/nvarchar(x) column then I wonder if it might also have a 1:1 relationship with the customer.
If I'm speculating too much here then feel free to dismiss this paragraph; but just in case, I want to say that if this data isn't properly normalized, normalizing it would make it much easier and faster to query on:
SELECT *
FROM Input
WHERE CustID NOT IN (SELECT CustID FROM Production)
Anyway, going back to the first query, since that's what we have to work with for now. Unfortunately it's impossible to create a join on those specific conditions in Linq, so we need to rewrite the SQL query as something slightly worse (because we now have to read from Input twice):
SELECT *
FROM Input
WHERE <Primary Key> NOT IN
(
SELECT i.<Primary Key>
FROM Input i
INNER JOIN Production p
ON (p.CustID = i.CustID OR (p.CustID IS NULL AND i.CustID IS NULL))
AND (p.CustName = i.CustName OR (p.CustName IS NULL AND i.CustName IS NULL))
AND (p.Household = i.Household OR
(p.Household IS NULL AND i.Household IS NULL))
)
Now we have something we can finally translate to Linq syntax. We still can't do the join explicitly, which would be best, but we go old-school, start from the cartesian join and toss the join conditions into the WHERE segment, and the server will still be able to sort it out:
var excluded =
from i in input
from p in production
where
((p.CustID == i.CustID) || ((p.CustID == null) && (i.CustID == null))) &&
((p.CustName == i.CustName) ||
((p.CustName == null) && (i.CustName == null))) &&
((p.Household == i.Household) ||
((p.Household == null) && (i.Household == null)));
select i.PrimaryKey;
var results =
from i in input
where !excluded.Contains(i.PrimaryKey)
select i;
I'm assuming here that you have some sort of primary key on the table. If you don't, you've got other problems, but you can get around this particular problem using EXCEPT:
var excluded =
from i in input
from p in production
where
((p.CustID == i.CustID) || ((p.CustID == null) && (i.CustID == null))) &&
((p.CustName == i.CustName) ||
((p.CustName == null) && (i.CustName == null))) &&
((p.Household == i.Household) ||
((p.Household == null) && (i.Household == null)));
select i;
var results = input.Except(excluded);