Convert SQL Server query to Linq query - sql

Question

select c.Name, d.First_Name, COUNT(c.Name) as qty
from order_product_s a
inner join Order_s b on a.Order_Id = b.Id
inner join Product_s c on a.Product_Id = c.Id
inner join Customer_s d on b.Customer_Id = d.Id
where b.Customer_Id = 4869
group by c.Name, d.First_Name

Answer 1

Something like this:
int __UserId = 4869;
var results =
(
from t in
(
from a in Repo.order_product_s
from b in Repo.Order_s
.Where(bb=> bb.id == a.Order_Id)
from c in Repo.Product_s
.Where(cc => cc.Id == a.Product_Id)
from d in Repo.Customer_s
.Where(dd => dd.Id == b.Customer_Id)
where b.Customer_Id == __UserId
select new
{
Name = c.Name
,First_Name = d.First_Name
}
)
group t by new { t.Name , t.First_Name } into g
select new
{
Name = g.Key.Name
,First_Name=g.Key.First_Name
,qty = g.Count( x => x.Name != null)
}
).ToList();
or more compact:
var results =
(
from a in Repo.order_product_s
from b in Repo.Order_s
.Where(bb=> bb.id == a.Order_Id)
// .DefaultIfEmpty() // <== makes join left join
from c in Repo.Product_s
.Where(cc => cc.Id == a.Product_Id)
// .DefaultIfEmpty() // <== makes join left join
from d in Repo.Customer_s
.Where(dd => dd.Id == b.Customer_Id)
// .DefaultIfEmpty() // <== makes join left join
where b.Customer_Id == __UserId
select new
{
Name = c.Name
,First_Name = d.First_Name
}
into t group t by new { t.Name , t.First_Name } into g
select new
{
Name = g.Key.Name
,First_Name=g.Key.First_Name
,qty = g.Count( x => x.Name != null)
// Or like this
// ,qty = g.Select(x => x.Name).Where(x => x != null).Count()
// and if you ever need count(distinct fieldname)
//,qty = g.Select(x => x.GroupName).Where(x => x != null).Distinct().Count()
}
)
// .OrderBy(t => t.Name).ThenBy(t => t.First_Name).ThenBy(t => t.qty) // Order in SQL
.ToList()
// .OrderBy(t => t.Name).ThenBy(t => t.First_Name).ThenBy(t => t.qty) // Order in .NET
;