C＃LINQ to SQL多个实体联接

Question

I have a table full of data split across year, brand and customer which I want to join with a customer master table. I want each output record to be customer, brand1 qty for the year, brand2 qty for the year, etc and a total of the brands. I created a class to recieve the output. When I view the data in the statistics table it has data which should meet the criteria used (ie debtorid, financialyearid and brandid.

My select currently looks like this

            var Debtors = Dbs.Debtors;
            var BikeSales = Dbs.SalesBikes.DefaultIfEmpty();
            if (sortStatePostCode)
            {
                dquery = from y in Debtors
                         from a in BikeSales where a.DebtorID == y.ID && a.FinYearID == finYear.ID && a.BikeBrandID == 1
                         from b in BikeSales where b.DebtorID == y.ID && b.FinYearID == finYear.ID && b.BikeBrandID == 2
                         from c in BikeSales where c.DebtorID == y.ID && c.FinYearID == finYear.ID && c.BikeBrandID == 3
                         from d in BikeSales where d.DebtorID == y.ID && d.FinYearID == finYear.ID && d.BikeBrandID == 4
                         from e in BikeSales where e.DebtorID == y.ID && e.FinYearID == finYear.ID && e.BikeBrandID == 7
                         from f in BikeSales where f.DebtorID == y.ID && f.FinYearID == finYear.ID && f.BikeBrandID == 8
                         from g in BikeSales where g.DebtorID == y.ID && g.FinYearID == finYear.ID && g.BikeBrandID == 9
                         from h in BikeSales where h.DebtorID == y.ID && h.FinYearID == finYear.ID && h.BikeBrandID == 10

                         orderby y.SortDelState == null ? "ZZZZ" : y.SortDelState, y.SortDelPCode == null ? "9999" : y.SortDelPCode, y.CustomerName
                         select new DealerBikeResult
                         {
                             LongYear = finyear,
                             CustomerCode = y.CustomerCode,
                             CustomerName = y.CustomerName,
                             City = y.SortDelCity,
                             PostCode = y.SortDelPCode,
                             State = y.SortDelState,
                             Terms = y.TermsCode,
                             Total = (
                                 (f == null ? 0 : (int)f.TotalQty) +
                                 (g == null ? 0 : (int)g.TotalQty) +
                                 (a == null ? 0 : (int)a.TotalQty) +
                                 (b == null ? 0 : (int)b.TotalQty) +
                                 (c == null ? 0 : (int)c.TotalQty) +
                                 (d == null ? 0 : (int)d.TotalQty) +
                                 (e == null ? 0 : (int)e.TotalQty) +
                                 (h == null ? 0 : (int)h.TotalQty)
                             ),
                             Bombtrack = f == null ? 0 : (int)f.TotalQty,
                             Fairdale = g == null ? 0 : (int)g.TotalQty,
                             Mirraco = a == null ? 0 : (int)a.TotalQty,
                             Radio = b == null ? 0 : (int)b.TotalQty,
                             Redline = c == null ? 0 : (int)c.TotalQty,
                             Sunday = d == null ? 0 : (int)d.TotalQty,
                             United = e == null ? 0 : (int)e.TotalQty,
                             WTP = h == null ? 0 : (int)h.TotalQty,
                             DealerBO = y.DealerBombTrack == null ? 3 : (int)y.DealerBombTrack,
                             DealerFA = y.DealerFairdale == null ? 3 : (int)y.DealerFairdale,
                             DealerMI = y.DealerMirraco == null ? 3 : (int)y.DealerMirraco,
                             DealerRA = y.DealerRadio == null ? 3 : (int)y.DealerRadio,
                             DealerRL = y.DealerRedline == null ? 3 : (int)y.DealerRedline,
                             DealerSU = y.DealerSunday == null ? 3 : (int)y.DealerSunday,
                             DealerUN = y.DealerUnited == null ? 3 : (int)y.DealerUnited,
                             DealerWP = y.DealerWTP == null ? 3 : (int)y.DealerWTP
                         };
            }

No matter what financialyearid I send to the query my return set is empty. I am able to get results when I create a view in SQL management studio which essentially achieves the same thing I want to get but I dont want to use views.

Could anyone point me in the right direction please. (Edited code to fix a few typos).

Several other posts have addressed the question in other ways (ie should you use multi-select or Join On etc.). I could not find a suitable Join On with multi column equals to work from and I need the three column selection which is why I have tried this way. Other posts have shown this method as achieving a join while others suggest this can't work.

Utilising Join ... On ... equals format has not worked for me with multiple columns or I would be using it.

Answer 1

Apart from the fact that you are not doing joins properly, that query where clause does not seems okay. Wasn't it supposed to be something like this ? -

from a in Dbs.SalesBikes.DefaultIfEmpty() where a.DebtorID == y.ID && finYear.ID == a.FinYearID && a.BikeBrandID == 1
from b in Dbs.SalesBikes.DefaultIfEmpty() where b.DebtorID == y.ID && b.FinYearID == finYear.ID && b.BikeBrandID == 2
from c in Dbs.SalesBikes.DefaultIfEmpty() where c.DebtorID == y.ID && c.FinYearID == finYear.ID && c.BikeBrandID == 3
from d in Dbs.SalesBikes.DefaultIfEmpty() where d.DebtorID == y.ID && d.FinYearID == finYear.ID && d.BikeBrandID == 4
from e in Dbs.SalesBikes.DefaultIfEmpty() where  e.DebtorID == y.ID && e.FinYearID == finYear.ID && e.BikeBrandID == 7
from f in Dbs.SalesBikes.DefaultIfEmpty() where  f.DebtorID == y.ID && f.FinYearID == finYear.ID && f.BikeBrandID == 8
from g in Dbs.SalesBikes.DefaultIfEmpty() where  g.DebtorID == y.ID && g.FinYearID == finYear.ID && g.BikeBrandID == 9
from h in Dbs.SalesBikes.DefaultIfEmpty() where  h.DebtorID == y.ID && h.FinYearID == finYear.ID && h.BikeBrandID == 10

Answer 2

I believe I found a post from one Jon Skeet which answers my question. Apparently I do need to use Join On syntax but what I was missing was the need to imitate transparent identifiers so that the preprocessor can be sure that datatypes are the same.

I shall try that now and make this the answer if it suceeds.

Again, kudos to Jon Skeet.