Linq to实体查询优化

Question

I've got a LINQ query that will select a ticket based on whether it satisfies a few conditions. The query itself runs fine and works okay, but I'm worried that with an increase in the number of possible returns it will get noticeably worse as it goes.

Could anyone suggest ways to improve or optimise this query to run faster/better? Am I doing something horribly wrong against standard practice?

Here's the query. I've swapped some names. I'm thinking that the select 's in select new statement are a problem as well.

var attentionObj = (from c in context.SupportTicketEntities
                    where
                    c.StatusID != 3 && 
                    ((c.IsAllocated == false)    // not allocated
                    || (c.FlaggedForAssist == true && c.AllocatedToEmployeeID == empId)     // is flagged for assist
                    || ((from d in c.SupportTicketDatas
                         where c.AllocatedToEmployeeID == empId
                         && c.FogBugzAttachments.Count == 0
                         orderby d.TimeStamp descending
                         select d.TimeStamp).FirstOrDefault() < warningDt)   // ticket not replied to
                    || ((from e in c.SupportTicketDatas
                         where c.AllocatedToEmployeeID == empId
                         orderby e.TimeStamp descending
                         select e).FirstOrDefault().RaisedByUser == true)   // customer has replied
                    || (c.IsEscalated == true))  // ticket escalated
                    select new
                    {
                        RefID = c.RefID,
                        TicketID = c.SupportTicketID,
                        ClientCompany = c.ClientData.Company,
                        IsAllocated = c.IsAllocated,
                        DateLogged = c.DateLogged,
                        IsFlagged = c.FlaggedForAssist,
                        NeedsReply = (from d in c.SupportTicketDatas
                                      orderby d.TimeStamp descending
                                      select d.TimeStamp).FirstOrDefault() < warningDt,
                        CustReply = (from e in c.SupportTicketDatas
                                     orderby e.TimeStamp descending
                                     select e).FirstOrDefault().RaisedByUser == true,
                        IsEscalated = c.IsEscalated
                    }).ToArray();

EDIT: So I've created a stored procedure, although I'm not the best at SQL. Is this okay?

@empId int,
@warningDt datetime
AS
SELECT * FROM SupportTickets
WHERE StatusID != 3
AND IsAllocated = 0
UNION
SELECT * FROM SupportTickets
WHERE StatusID != 3
AND FlaggedForAssist = 1
AND AllocatedToEmployeeID = @empId
UNION
SELECT * FROM SupportTickets
WHERE StatusID != 3
AND AllocatedToEmployeeID = @empId
AND NOT EXISTS (SELECT FogBugzLinkID FROM FogBugzAttachment)
AND (SELECT MAX(TimeStamp) 
 FROM SupportTicketData
 WHERE SupportTickets.SupportTicketID = SupportTicketData.SupportTicketID) < @warningDt
UNION
SELECT SupportTickets.* FROM SupportTickets
JOIN SupportTicketData ON SupportTickets.SupportTicketID = SupportTicketData.SupportTicketID
WHERE SupportTickets.StatusID != 3
AND SupportTickets.AllocatedToEmployeeID = @empId
AND SupportTicketData.TimeStamp = (SELECT MAX(TimeStamp) FROM SupportTicketData
                   WHERE SupportTickets.SupportTicketID = SupportTicketData.SupportTicketID)
AND SupportTicketData.RaisedByUser = 1
UNION
SELECT * FROM SupportTickets
WHERE StatusID != 3
AND SupportTickets.IsEscalated = 1

Answer 1

So it appears that using a stored procedure like the one in my initial statement is much much more efficient than using the hideous LINQ OR statement.

I'll mark this as the answer so it gets closed. Look at my original question for the SPROC.