Entity Framework calling MAX on null on Records

Question

When calling Max() on an IQueryable and there are zero records I get the following exception.

The cast to value type \'Int32\' failed because the materialize

Answer 1

Try this:

IEnumerable alerts = null;

    alerts = (from POA in SDSEntities.Context.SDS_PRODUCT_ORDER_ALERT
              join A in SDSEntities.Context.SDS_ALERT on POA.ALERT_ID equals A.ALERT_ID
              orderby POA.DATE_ADDED descending
              select new AlertsResultset
              {
                  ID = POA.PRODUCT_ORDER_ALERT_ID == null ? 0:POA.PRODUCT_ORDER_ALERT_ID ,
                  ITEM_ID = POA.ORDER_ID.HasValue ? POA.ORDER_ID.Value : POA.PRODUCT_ID.Value,
                  Date = POA.DATE_ADDED.Value,
                  orderType = SDSEntities.Context.SDS_ORDER.Where(o => o.ORDER_ID == POA.ORDER_ID.Value).FirstOrDefault().ORDER_TYPE,
                  TransactionNumber = POA.PRODUCT_ID.HasValue ? (SDSEntities.Context.SDS_PRODUCT.Where(p => p.PRODUCT_ID == POA.PRODUCT_ID.Value).FirstOrDefault().TRANSACTION_NUMBER) : (SDSEntities.Context.SDS_ORDER.Where(o => o.ORDER_ID == POA.ORDER_ID.Value).FirstOrDefault().TRANSACTION_NUMBER),
                  Publisher = POA.PRODUCT_ID.HasValue ?
                  (
                  SDSEntities.Context.SDS_PRODUCT.Where(p => p.PRODUCT_ID == POA.PRODUCT_ID.Value).FirstOrDefault().PRODUCT_TYPE_NUMBER == "ISSUE" ? (from prod in SDSEntities.Context.SDS_PRODUCT
                                                                                                                                                      join ji in SDSEntities.Context.SDS_JOURNAL_ISSUE on prod.PRODUCT_ID equals ji.PRODUCT_ID
                                                                                                                                                      join j in SDSEntities.Context.SDS_JOURNAL on ji.JOURNAL_ID equals j.JOURNAL_ID
                                                                                                                                                      where prod.PRODUCT_ID == POA.PRODUCT_ID
                                                                                                                                                      select new { j.PUBLISHER_NAME }).FirstOrDefault().PUBLISHER_NAME : (from prod in SDSEntities.Context.SDS_PRODUCT
                                                                                                                                                                                                                          join bi in SDSEntities.Context.SDS_BOOK_INSTANCE on prod.PRODUCT_ID equals bi.PRODUCT_ID
                                                                                                                                                                                                                          join b in SDSEntities.Context.SDS_BOOK on bi.BOOK_ID equals b.BOOK_ID
                                                                                                                                                                                                                          where prod.PRODUCT_ID == POA.PRODUCT_ID
                                                                                                                                                                                                                          select new { b.PUBLISHER_NAME }).FirstOrDefault().PUBLISHER_NAME
                  )
                  : (SDSEntities.Context.SDS_ORDER.Where(o => o.ORDER_ID == POA.ORDER_ID.Value).FirstOrDefault().PUBLISHER_NAME),
                  Alert = A.ALERT_NAME,
                  AlertType = A.ALERT_TYPE,
                  IsFlagged = POA.IS_FLAGGED.Value,
                  Status = POA.ALERT_STATUS
              });