SQL Query Optimization taking 20 - 30 secs to run - sql

Question

Below query takes 20 secs to execute and i need to optimize it as much as i can. Please help me on this.
SELECT Distinct
qh.QuoteHeaderId, [dbo].[mpx2_Get_PhoneGrade](qh.QuoteHeaderId)
FROM
t_QuoteHeader QH
INNER JOIN
t_HandsetQuote h ON Qh.QuoteHeaderId = h.QuoteHeaderId
INNER JOIN
t_phoneAudit P ON ISNULL(h.InspectionPhoneAuditId, h.QuotePhoneAuditId) = p.PhoneAuditId
INNER JOIN
mpx2_vw_customers C ON qh.CustomerId = C.CustomerId
INNER JOIN
#ContactChannels CC ON C.ContactChannelId = CC.ContactChannelId
LEFT OUTER JOIN
t_HandsetQuoteAdditionalInfo_TRNX hqa ON hqa.hqid = h.HandsetQuoteId
WHERE
((#VirtualStatusId = 0 OR #VirtualStatusId = -2 OR
C.ContactChannelId NOT IN (1, 2, 13, 80)))
AND ((#VirtualStatusId = -2) OR
('Q'+ CAST(Qh.QuoteStatusId AS VARCHAR(3)) + 'S' + CAST(h.StockStatusId AS VARCHAR(3)) IN
(SELECT 'Q'+ CAST(QuoteStatusId AS VARCHAR(3)) + 'S' + CAST(StockStatusId AS VARCHAR(3)) FROM t_VirtualStatusMap WHERE (#VirtualStatusId IS NULL OR #VirtualStatusId IN (0,-1) OR VirtualStatusId = #VirtualStatusId))
)
)
AND ((qh.IsCancelled = 0 and #onlyOpenOrders = 1) OR #onlyOpenOrders = 0)
AND ((h.IsCancelled = 0 and #onlyOpenOrders = 1) OR #onlyOpenOrders = 0)
AND (qh.ConfirmedDate <= #CutOff)
Please help me to optimize it. This query is used in a stored procedure.

Answer 1

This is too long for a comment.
ORs in WHERE and ON clauses are very hard to optimize. Often with a query like this, it is better to construct the query based on the components and use dynamic SQL.
For instance, the condition on #OnlyOpenOrders would be included like this:
declare #sql varchar(max);
set #sql = ' . . .';
declare #where varchar(max);
set #where = 'where . . .';
if (#OnlyOpenOrders = 0) begin
set #where = #where + ' and qh.IsCancelled = 0 and h.IsCancelled = 0'
end;
set #sql = #sql + ' ' + #where;
exec sp_executesql #sql;
You need to have similar logic for all the variables you are using.

Answer 2

There are a couple of things, although as others have said without all the required information such as a full execution plan, and schemas of the tables involved it is mostly guidelines/guesswork;
1.) In this part, it would appear you build a string from QuoteStatusId and StockStatusId in order to compare them;
('Q'+ CAST(Qh.QuoteStatusId AS VARCHAR(3)) + 'S' + CAST(h.StockStatusId AS VARCHAR(3))
IN
(SELECT 'Q'+ CAST(QuoteStatusId AS VARCHAR(3)) + 'S' + CAST(StockStatusId AS VARCHAR(3))
FROM t_VirtualStatusMap
WHERE (#VirtualStatusId IS NULL
OR #VirtualStatusId IN (0,-1) OR VirtualStatusId = #VirtualStatusId)))
If you skipped building the strings, since they are comprised of the same two columns and just compared the two columns directly that may speed things up.
2.) Have you tried adding the index which it suggests in the picture you attached? Without seeing your schema and an execution plan it is hard to suggest appropriate ones but it might be worth adding the one suggested (right click the green writing and it will generate the code to add the suggested index). I would read up on indexes and ensure there is an appropriate index for the query to use. ConfirmedDate seems like an obvious one, as well as all the join keys.
3.) As Gordon suggested using dynamic sql or if you are not comfortable with that - maybe splitting the query out into a few queries and switching between each using an IF statement, could help SQL generate a good plan for each scenario, instead of trying to find a generic plan to work for all cases.