LINQ version of SQL with left join and group by

Question

Can any one tell me the linq query for this sql?

select 
  t1.item, 
  IsNull(sum(t2.price), 0) total
from table1 t1
left join table2 t2
  on t1.id = t2.itemid
group by t1.item

Answer 1

LINQ version of your SQL query,

var resutl = from t1 in objtable1
                     join t2 in objtable2 on t1.id equals t2.itemid into j1
                     from j2 in j1.DefaultIfEmpty()
                     group j2 by t1.item into grouped
                     select new { item = grouped.Key,  sum =  grouped.Sum(t => t != null ? (t.price ??0 ) : 0) };

If you have value (id) in table1 but not in table2 (itemid) then t inside grouped.Sum() will be null so you need to check if t is not null and t.price also is not null inside grouped.sum()

Answer 2

Use it as

var result = (from t1 in table1 
                      join t2 in table2 on t1.id equals t2.itemId
                     into t2d from td in t2d.DefaultIfEmpty()
                     group t1 by t1.item into t1g select new {item=t1g.key, sum =t1g.Sum(p=>p.price??0)} ).ToList();