I have got this SQL statement which I am trying to convert to LINQ.
SELECT *
FROM History
WHERE Status = 'Created' AND HistoryId IN (1, 2, 3);
I have not been able to do the IN part. Tried following but I am unable to complete it:
var list = new List<int>() { 1, 2, 3};
var result = db.History.Where(x => x.Status == 'Created' && )
How do I write IN part of SQL in LINQ?
You can use Contains:
var result = db.History.Where(x => x.Status == 'Created' && list.Contains(x.HistoryId))
Related
I have a SQL query which I want to convert to Linq.
This is my SQL query:
SELECT
Calisanlar.CalisanId,
CovidYakalanmaTarih,
CovidBitisTarih
FROM
Calisanlar
INNER JOIN
Covids ON Calisanlar.CalisanId = Covids.CalisanId
WHERE
Calisanlar.CalisanId IN (SELECT TOP 10 CalisanId
FROM Hastaliklar
GROUP BY CalisanId
ORDER BY COUNT(*) DESC)
AND DATEDIFF(DAY, CovidYakalanmaTarih, GETDATE()) BETWEEN 0 AND 30
I wrote this C# code, but it doesn't work as expected because i didn't write "DATEDIFF(DAY, CovidYakalanmaTarih, GETDATE()) BETWEEN 0 AND 30" linq version:
var query = context.Hastaliklar
.GroupBy(x => x.CalisanId)
.OrderByDescending(grp => grp.Count())
.Select(grp => grp.Key)
.Take(10)
.ToList();
var result = from hastalik in context.Hastaliklar
join covid in context.Covids
on hastalik.CalisanId equals covid.CalisanId
where query.Contains(hastalik.CalisanId)
&& EF.Functions.DateDiffDay(covid.CovidYakalanmaTarih, covid.CovidBitisTarih)
select new SonBirAyCovidDto
{
CalisanId = covid.CalisanId,
CovidYakalanmaTarih = covid.CovidYakalanmaTarih,
CovidBitisTarih = covid.CovidBitisTarih
};
There is not direct translation to BETWEEN in EF Core, but you can make other condition. Also it is better to remove ToList() from first query, in this case you will have only one roundtrip to database.
var query = context.Hastaliklar
.GroupBy(x => x.CalisanId)
.OrderByDescending(grp => grp.Count())
.Select(grp => grp.Key)
.Take(10);
var result =
from hastalik in context.Hastaliklar
join covid in context.Covids
on hastalik.CalisanId equals covid.CalisanId
where query.Contains(hastalik.CalisanId)
&& covid.CovidYakalanmaTarih <= covid.CovidBitisTarih
&& EF.Functions.DateDiffDay(covid.CovidYakalanmaTarih, covid.CovidBitisTarih) <= 30
select new SonBirAyCovidDto
{
CalisanId = covid.CalisanId,
CovidYakalanmaTarih = covid.CovidYakalanmaTarih,
CovidBitisTarih = covid.CovidBitisTarih
};
I want to convert this SQL query to LINQ. But I'm new in EF. Please help
SQL Query
select * from VersionHistory where id in( select OptionsId from StylesHistory where ConId=540 and OptionsId = 28286 and ModifiedAtVersion>1)
TIA
I tried Something like this
var stylesHistory = _context.VersionHistory
.Where(x => x.ModifiedAtVersion > 1
&& x.Id==28286
&& x.Contract.Id==540)
.ToList()
Not Sure How I can add Sub Query
You can easily write that as:
var result = ctx.VersionHistory
.Where(vh => ctx.StylesHistory
.Any( sh => sh.OptionsId == vh.Id &&
sh.OptionsId == 28286 &&
sh.ConId = 540 &&
sh.ModifiedAtVersion > 1));
You can also create your subquery as another IEnumerable which you'll use in the main query.
This will improve readibility.
EF will only generate one query.
I have a SQL Server query like this:
select
month(fact_date) as month,
sum(case when beef_dairy_stat = 1 and param_id = 1 then 1 else 0 end) as cnt
from
user_behave_fact
where
YEAR(fact_date) = 2018
group by
month(fact_date)
order by
month
with a result of
month cnt
------------
1 10
2 20
Now I need to convert this query to its corresponding Entity Framework query.
This is my current attempt:
var sql_rez_ICC = new List<Tuple<int, int>>();
sql_rez_ICC = db.user_behave_fact
.Where(x => x.fact_date.Value.Year == selected_year)
.GroupBy(y => y.fact_date.Value.Month)
.Select(y =>new { month = y.Select(x=>x.fact_date.Value.Month), icc_count = y.Count(x => x.beef_dairy_stat == true && x.param_id == 1) })
.AsEnumerable()
.Select(y => new Tuple<int, int>(y.month, y.icc_count))
.ToList();
However on second .Select, I get an error on month which is
Cannot convert from System.Collection.Generic.IEnumrable to int
y.Select(x=>x.fact_date.Value.Month) returns an IEnumerable<int>. Use y.Key instead.
here's my sql query below:
Can you guys help me to convert this to a much cleaner one??
SELECT [PurchaseRequestID], [ProjectID],[FullName]
FROM PurchaseRequest
WHERE [PurchaseRequestID] IN
(SELECT [PurchaseRequestID] FROM PurchaseRequestDetail )
AND [PurchaseRequestID] NOT IN
(SELECT [PurchaseRequestID] FROM [PurchaseOrder] )
Though i have already converted this successfuly, i think this is not readable and needs to be rewritten:
var query = from a in db.PurchaseRequests
where
(from b in db.PurchaseRequestDetails
select new
{
b.PurchaseRequestID
}).Contains(new { a.PurchaseRequestID }) &&
!(from c in db.PurchaseOrders
select new
{
c.PurchaseRequestID
}).Contains(new { a.PurchaseRequestID })
select a;
thanks
you really don't need all those anonymous objects. Use the let keyword to introduce temporary variables instead of doing operations on the subqueries directly.
from a in db.PurchaseRequests
let b = from b in db.PurchaseRequestDetails select b.PurchaseRequestID
let c = from c in db.PurchaseOrders select c.PurchaseRequestID
where b.Contains(a.PurchaseRequestID) && !c.contains(a.PurchaseRequestID)
select a;
var query = from a in db.PurchaseRequests
where
db.PurchaseRequestDetails.Any(x => x.PurchaseRequestID == a.PurchaseRequestID) &&
!db.PurchaseOrders.Any(x => x.PurchaseRequestID == a.PurchaseRequestID)
select a;
If you have navigation properties set up, you can write the query like this:
IQueryable<PurchaseRequest> query =
from purchaseRequest in myDataContext.PurchaseRequests
where purchaseRequest.PurchaseRequestDetail.Any()
where !purchaseRequest.PurchaseOrder.Any()
select purchaseRequest;
Or this lambda/method style if you prefer...
IQueryable<PurchaseRequest> query2 = myDataContext.PurchaseRequests
.Where(purchaseRequest => purchaseRequest.PurchaseRequestDetail.Any())
.Where(purchaseRequest => !purchaseRequest.PurchaseOrder.Any());
I don't know how to work with nested selects in LINQ.
How could I convert this SQl expression to LINQ?
Select i.ID, i.Impression,
(Select COUNT(ImpressionsId)
from DiaryImpressions
where DiaryPostsId = '2' AND ImpressionsId = i.ID) as Num from Impressions i
Seriously? DiaryPostsId is a string? Oh well...
from i in context.Impressions
select new {
i.ID,
i.Impressions,
Num = (from d in context.DiaryImpressions
where d.DiaryPostsId == "2"
&& d.ImpressionsId == i.ID
select d).Count()
}
from ...
select new {
i.Id,
i.Impression,
Count = context.DiaryImpressions.Count(d => d.DiaryPostsId == 2 && d.ImpressionsId == i.Id)
}
If you map your objects properly, you can use child relations directly:
Count = i.DiaryImpressions.Count(d => d.DiaryPostsId == 2)