sql语句转成linq
select SUM(P.W) as w from order o left join product p on o.pid=p.ID where o.oid=100这个sql语句怎么转成Linq啊？求教
[解决办法]
你用LINQPAD
VLinq
http://www.alinq.org/en/default.aspx
可以转！
[解决办法]

(from o in order 
join p in product
on o.pid equals p.ID
into temp
from temp.DefaultIfEmpty
where o.oid==100
select temp.W).Sum(x=>x.W);

[解决办法]

引用:

引用:
select SUM(P.W) as w from order o left join product p on o.pid=p.ID where o.oid=100这个sql语句怎么转成Linq啊？求教


var query=(order.AsEnumerable().where(c=>c.oid==100)
join product.A……

改下：
var query=(order.AsEnumerable().where(c=>c.oid==100)
join product.AsEnumerable() on order.Field<int>("pid") equals product.Field<int>("pid")
select product.Field<int>("w")).Sum();
[解决办法]

引用:

select SUM(P.W) as w from order o left join product p on o.pid=p.ID where o.oid=100这个sql语句怎么转成Linq啊？求教

var query = (from o in order.Where(x=>x.oid==100)
            join p in product 
            on o.pid equals p.ID into t
            from p in t.DefaultIfEmpty()
            select p.W).Sum();