I have a sql having left outer join, I want to convert it to linq. the sql is
Select P.Surname, P.Othername H.history
from customers P left outer join historyfiles H on H.patID = P.patId
and H.category1 = 4
where P.id = 2299
Thank you very much.
You can try this:
var query = from p in db.customers.Where(t => t.id == 2299 )
join h in db.historyfiles.Where(l => l.category1 == 4 ) on p.patID equals h.patID into gj
from h in gj.DefaultIfEmpty()
select new { p.Surname, p.Othername, h.History };
Related
I am trying to convert this tSql command to linq query.
I want to group this columns.
Can you help me?
select vUnit.FK_Unit_ID , Unit.unitNumber, unit.unitTitle , title.featureTitleName
from unit.UnitFeatureValue vUnit
inner join unit.Unit on vUnit.FK_Unit_ID = Unit.ID
inner join unit.FeatureTitle title on vUnit.FK_FeatureTitle_ID = title.ID
where vUnit.FK_Unit_ID = 15 and title.canMoreSelect = 1
group by vUnit.FK_Unit_ID ,unit.unitNumber, unit.unitTitle , title.featureTitleName
var query = (
from v in dbContext.UnitFeatureValue
join u in dbContext.Unit on v.FK_Unit_ID equals u.ID
join t in dbContext.FeatureTitle on v.FK_FeatureTitle_ID equals t.ID
where v.FK_Unit_ID == 15 && t.canMoreSelect == 1
select new {
v.FK_Unit_ID,
u.unitNumber,
u.unitTitle,
t.featureTitleName,
}).Distinct();
something like this
var result = (from v in vUnit
join u in unit on v.FK_Unit_ID equals u.ID
join t in title on v.FK_FeatureTitle_ID equals t.ID
where v.FK_Unit_ID == 15 and t.canMoreSelect == 1
select new { v.FK_Unit_ID , u.unitNumber, u.unitTitle , t.featureTitleName }).ToList();
sql
select * from (select * from tabla limit 1) as a inner join table b on a.id = b.id where a.id = id
LINQ
from s in tableA
join c in (from a in tableB where a.id==id select a).FirstOrDefault() on s.id equals c.id
where s.id == id
select s
I want to translate this sql to linq but failed. How can I do translate?
I think this will do it, but you should check what sql is being generated by linq.
a = tableA.FirstOrDefault();
//First option
tableB.Where(xb => xb.id = a.id)
.Select(xb => new {a = a, b = xb})
.Where(abx => abx.a.id == id)
//Second option
tableB.Select(xb => new {a = a, b = xb})
.Where(abx => abx.a.id == id && abx.a.id = abx.b.id)
I want to convert this code to linq:
select t1.title, COUNT(*)as num
from t1 INNER join t2 on t2.gId = t1.Id
group by t1.title, t1.cId
having t1.cId = 2
I tried this below code:
from p in db.t1s join r in db.t2s on p.Id equals r.gId
where p.cId == 2
group p by p.title into g
select new{ name = from o in g select o.title, num = g.Count()}
But this doesn't return COUNT correctly.
please guide me how can I solve the problem
thanks
Without sample data its hard to get it right, but try this snippet
from p in db.t1s
join r in db.t2s on p.Id equals r.gId
where p.cId == 2
group p by new {p.title, p.cId} into grouped
select new{ name = grouped.Key.title, num = grouped.Count()}
Also, note that this sql:
select t1.title, COUNT(*)as num
from t1 INNER join t2 on t2.gId = t1.Id
group by t1.title, t1.cId
having t1.cId = 2
Will always return 1 as result of COUNT(*). The reason is that you have filtering t1.cId = 2 and grouping by t1.cId as second parameter.
I have 3 tables which named Player, PlayerDetails and Team. I want to write a linq statement such as
from p in Player join d in PlayerDetails on p.ID equals d.PID
and then right join team table, Player has a column named TID which face to Team table's ID.
I have tried to write a statement like
from p in Player join d in PlayerDetails on p.ID equals d.PID into PlayerGroup
from t in team join g in PlayerGroup on t.ID equals g.p.ID
It certainly can't work. I'm not sure how to write such type of query statement, table left join table2 then right join table3.
Who can help?
I believe you could do something like this:
var LeftJoin =
from p in Player
join d in PlayerDetails on p.ID equals d.PID into pd
from d in pd.DefaultIfEmpty()
select new
{
pID = p.ID,
pTID = p.TID,
dID = d.ID
};
var RightJoin =
from t in Team
join l in LeftJoin on t.ID equals l.pTID into tl
from l in tl.DefaultIfEmpty()
select new
{
tID = t.ID,
pID = l.pID,
pTID = l.PTID,
dID = l.dID
};
To do everything in one query, I think you could do (not tested) something like this:
var RightJoin =
from t in Team
join l in
(from p in Player
join d in PlayerDetails on p.ID equals d.PID into pd
from d in pd.DefaultIfEmpty()
select new
{
pID = p.ID,
pTID = p.TID,
dID = d.ID
})
on t.ID equals l.pTID into tl
from l in tl.DefaultIfEmpty()
select new
{
tID = t.ID,
pID = l.pID,
pTID = l.PTID,
dID = l.dID
};
I need to convert some SQL statement to LINQ. How convert LEFT OUTER JOIN to equivalent LINQ statement?
You need to use the DefaultIfEmpty operator. The below code should result in a left outer join.
var q = from c in customers
join o in orders on c.Key equals o.Key into g
from o in g.DefaultIfEmpty()
select new {Name = c.Name, OrderNumber = o == null ? "(no orders)" : o.OrderNumber};
Credit to: http://www.hookedonlinq.com/OuterJoinSample.ashx