create table Tab (
id int prinary key,
amount money
) 

from c in Tab
where TakeWhile(c => sum(c) <=SumAll)
select c

        decimal sum_row =  0 ;
        decimal sum(decimal pack_amount)
        {
            return sum_row += pack_amount;
        }
void Calc()
{
var query  =
(from c in db.Tabs
select new{c.id, c.amount , sum_amount = sum(c.amount )}).ToList().Where( ost=> ost. sum_amount<=ОБЩАЯ СУММА) 
 

}

create table tab(\nid int identity( 1 , 1 ) primary key,\namount money\n)

var query =
                from c in db.tabs
                where (
                from s in db.tabs
                where s.id < c.id
                select s).Sum(s => s.amount) <  10 
                select c;

create table tab(
id int identity( 1 , 1 ) primary key,
amount money
)