SQL filtering data - sql

Question

I need some advice on how to query a database more efficiently.
The situation can be explained as this. If a customer comes into the store and buys something that creates a sale in the [sales table] this table links via transaction reference to [transactions table] but there may be a number of items purchased, each of these creates a row in the [products table].
To add to this there are also two promotion tables that indicate whether the product is on price promotion [promotions] or on a multibuy promotion[sales flag]. Both of these also link back to the sales table.
I want to be able to bring back all the rows so every product of every transaction that was in one of the promotions is available.
The conditions work as follows
Product ¦ Price promo (promotions-promotion no) ¦Multibuy(salesflag-On promotion)
-----------------------------------
1.Product A -1 0 = neither price promo nor multibuy
2.Product B -1 1 = multibuy only ie 0 false 1 true
3.Product C 8245 0 = price promo only can be any number other than -1
These are the three scenarios yet they could all happen in one customer transaction.
so how could I check every transaction for the circumstances of products B and C and return the full basket if either is present?
All I can think to do is a further select within the where clause but this would return all the relevant transaction numbers and the main query would then search the entire database for these transaction numbers it seems a very long winded way as it is a huge database I'm working on + I'm fairly basic level sql at the moment.
SELECT
TRANS.TransactionReference
,TRANS.TID
,CONVERT(VARCHAR(10),T.Day,103) as 'Date'
,PROD.HierarchyLevel2
,PROD.HierarchyLevel3
,PROD.HierarchyLevel4
,PROD.ProductDescription
,PROD.ExternalProductCode
,PROD.Size
,CUST.CardNumber
,S.SalesQty /*unless Group everything somehow will get multiple lines per qty sold all with qty of 1*/
,S.SalesValue
,STOR.Area
,STOR.StoreCode
,STOR.StoreName
FROM Reporting.Sales as S
INNER JOIN Reporting.Products as PROD
on S.ProductID = PROD.ProductID
INNER JOIN Reporting.Time as T
on S.DateID = T.DateID
INNER JOIN Reporting.Stores as STOR
on S.StoreID = STOR.StoreID
INNER JOIN Reporting.Promotions as PROM
on S.PromotionID = PROM.PromotionID
INNER JOIN Reporting.SalesFlags as FLAG
on S.SalesFlagID = FLAG.SalesFlagID
INNER JOIN Reporting.Transactions as TRANS
on S.TID = TRANS.TID
INNER JOIN Reporting.Customers as CUST
on S.CustomerID = CUST.CustomerID
WHERE
T.Day BETWEEN '2014-01-23' and '2014-02-11'
AND TRANS.TransactionReference IN(SELECT distinct TRANS.TransactionReference
FROM Reporting.Sales as S
INNER JOIN Reporting.Transactions as TRANS
on S.TID = TRANS.TID
INNER JOIN Reporting.Promotions as PROM
on S.PromotionID = PROM.PromotionID
INNER JOIN Reporting.SalesFlags as FLAG
on S.SalesFlagID = FLAG.SalesFlagID
INNER JOIN Reporting.Time as T
on S.DateID = T.DateID
WHERE
PROM.PromotionNumber = '-1'
AND FLAG.OnPromotion = 1)
AND T.Day BETWEEN '2014-01-23' and '2014-02-11'
ORDER BY
TRANS.TransactionReference
;
The above would only take account of the sales where a basket contained a multibuy and i havent worked through how to include the sales where the basket can also contain a price promo. But already I'm leaving the query for 10 minutes and getting no results back- just keeps running.
The inner joins I have used I believe are all primary keys as the database has been set up cleverly to all link back to the sales table through keys built into this table.
Thanks in advance,
Kind regards,
Adam.