Click here to monitor SSC
SQLServerCentral is supported by Red Gate Software Ltd.
 
Log in  ::  Register  ::  Not logged in
 
 
 
        
Home       Members    Calendar    Who's On


Add to briefcase 12345»»»

Find Customers Who Bought "A" and "B" But Not "C" (SQL Spackle) Expand / Collapse
Author
Message
Posted Wednesday, March 28, 2012 9:51 PM


SSC-Dedicated

SSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-DedicatedSSC-Dedicated

Group: General Forum Members
Last Login: Today @ 12:18 AM
Points: 36,751, Visits: 31,202
Comments posted to this topic are about the item Find Customers Who Bought "A" and "B" But Not "C" (SQL Spackle)

--Jeff Moden
"RBAR is pronounced "ree-bar" and is a "Modenism" for "Row-By-Agonizing-Row".

First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column."

(play on words) "Just because you CAN do something in T-SQL, doesn't mean you SHOULDN'T." --22 Aug 2013

Helpful Links:
How to post code problems
How to post performance problems
Post #1274832
Posted Wednesday, March 28, 2012 9:56 PM
SSC Rookie

SSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC Rookie

Group: General Forum Members
Last Login: Wednesday, July 9, 2014 2:50 PM
Points: 40, Visits: 343
@Jeff

Did you compare the speed of this query against one where your first (Group By) From clause is a Select Distinct (sub) query?

Nice article. It builds nicely for the reader.

I love seeing the Except clause being introduced to the reader who, like me, cut our teeth on SQL92 and need to learn newer language features to be more productive.



Post #1274833
Posted Wednesday, March 28, 2012 10:17 PM
SSC Veteran

SSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC VeteranSSC Veteran

Group: General Forum Members
Last Login: Friday, May 23, 2014 11:13 PM
Points: 229, Visits: 208
Another way to get the result would be to use Intersect and then combine it with Except. The distinct part is handled implicitly.

--===== Find Customers that bought both "A" AND "B"
SELECT CustomerID
FROM #Purchase
WHERE ProductCode IN ('A')
INTERSECT
SELECT CustomerID
FROM #Purchase
WHERE ProductCode IN ('B')
EXCEPT
--===== Find Customers that bought "C".
SELECT CustomerID
FROM #Purchase
WHERE ProductCode IN ('C')
;

Post #1274836
Posted Wednesday, March 28, 2012 10:53 PM
UDP Broadcaster

UDP BroadcasterUDP BroadcasterUDP BroadcasterUDP BroadcasterUDP BroadcasterUDP BroadcasterUDP BroadcasterUDP Broadcaster

Group: General Forum Members
Last Login: Sunday, June 29, 2014 11:26 PM
Points: 1,481, Visits: 1,960
Wouldnt something like this work just as well?
SELECT 
CustomerId
FROM #Purchase
WHERE ProductCode IN ('A','B', 'C')
GROUP BY CustomerID
having sum(case when ProductCode = 'A' then 1 else 0 end) > 0
and sum(case when ProductCode = 'B' then 1 else 0 end) > 0
and sum(case when ProductCode = 'C' then 1 else 0 end) = 0

/T
Post #1274846
Posted Wednesday, March 28, 2012 11:04 PM
SSCrazy

SSCrazySSCrazySSCrazySSCrazySSCrazySSCrazySSCrazySSCrazy

Group: General Forum Members
Last Login: Tuesday, July 22, 2014 9:03 PM
Points: 2,262, Visits: 5,405
tommyh (3/28/2012)
Wouldnt something like this work just as well?
SELECT 
CustomerId
FROM #Purchase
WHERE ProductCode IN ('A','B', 'C')
GROUP BY CustomerID
having sum(case when ProductCode = 'A' then 1 else 0 end) > 0
and sum(case when ProductCode = 'B' then 1 else 0 end) > 0
and sum(case when ProductCode = 'C' then 1 else 0 end) = 0

/T

Yep, this is how i once implemented it! Cant remember the thread now.

Here it is: http://www.sqlservercentral.com/Forums/FindPost1267224.aspx

Proved to elimate the EXCEPT part; also does a single scan on the table.
Post #1274850
Posted Wednesday, March 28, 2012 11:53 PM


SSChampion

SSChampionSSChampionSSChampionSSChampionSSChampionSSChampionSSChampionSSChampionSSChampionSSChampion

Group: General Forum Members
Last Login: Yesterday @ 6:51 AM
Points: 13,252, Visits: 10,135
Nice spackle Jeff, and great alternatives in the discussion!



How to post forum questions.
Need an answer? No, you need a question.
What’s the deal with Excel & SSIS?

Member of LinkedIn. My blog at LessThanDot.

MCSA SQL Server 2012 - MCSE Business Intelligence
Post #1274872
Posted Wednesday, March 28, 2012 11:55 PM
SSCrazy

SSCrazySSCrazySSCrazySSCrazySSCrazySSCrazySSCrazySSCrazy

Group: General Forum Members
Last Login: Tuesday, July 22, 2014 9:03 PM
Points: 2,262, Visits: 5,405
OH yeah, Nice one Jeff. As always! Thanks a lot for taking time to teach us some of the tricks of the game. Thaks a lot :)
Post #1274873
Posted Thursday, March 29, 2012 12:37 AM
SSC-Addicted

SSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-AddictedSSC-Addicted

Group: General Forum Members
Last Login: Tuesday, July 15, 2014 1:10 AM
Points: 401, Visits: 546
Had a play with this and was very impressed - nice job.

I played around and added this index
CREATE INDEX IX_#Purchase_ProductCode
ON #Purchase (
ProductCode)
INCLUDE (CustomerID)

One concern I had was looking at the query plan, the EXCEPT does a clustered index scan. That may be a function of the small data set, but I am not sure.

My preference for these types of queries has always been to do an OUTER JOIN on the one we don't want selected and then say that we only want the ones that didn't match returned.

SELECT a.CustomerID
FROM #Purchase a
LEFT OUTER JOIN #Purchase b
ON b.CustomerID = a.CustomerID
AND b.ProductCode IN ('C')
WHERE a.ProductCode IN ('A','B')
AND b.CustomerID IS NULL
GROUP BY a.CustomerID
HAVING COUNT(DISTINCT a.ProductCode) = 2

Any thoughts?
Post #1274889
Posted Thursday, March 29, 2012 1:07 AM
Grasshopper

GrasshopperGrasshopperGrasshopperGrasshopperGrasshopperGrasshopperGrasshopperGrasshopper

Group: General Forum Members
Last Login: Monday, July 15, 2013 6:08 PM
Points: 14, Visits: 73
"Left Join Where Is Null" gets complicated to read/understand and is subject to cardinalities issues that will impact performance if the right set has many records for 1 record in the left hand side.

There is also this way, probably the closest to natural language.

Select	Distinct
CustomerID
From #Purchase
Where ProductCode = 'A'
And CustomerID In
(
Select CustomerID
From #Purchase
Where ProductCode = 'B'
)
And CustomerID Not In
(
Select CustomerID
From #Purchase
Where ProductCode = 'C'
)



I would be interested to have this table filled by 100,000+ rows of sample data and then compare execution plans and statistics of the proposed approaches.
Comparing syntax without an idea of the performance signature is a bit useless IMHO.

So here is another version of the initialization script from which the difference will be more blatant:
--===== Conditionally drop the test table to make
-- reruns in SSMS easier.
IF OBJECT_ID('tempdb..#Purchase','U') IS NOT NULL
DROP TABLE #Purchase
;
--===== Create the test table
CREATE TABLE #Purchase
(
PurchaseID INT IDENTITY(1,1),
CustomerID INT,
ProductCode VARCHAR(1000)
PRIMARY KEY CLUSTERED (PurchaseID)
)
;

--===== Populate the test table with known data.
INSERT INTO #Purchase
(CustomerID, ProductCode)
------- Customer #1 precisely meets the criteria.
-- Bought 'A' and 'B' but not 'C'.
SELECT 1, 'A' UNION ALL
SELECT 1, 'B' UNION ALL
------- Customer #2 also meets the criteria.
-- Bought 'A' and 'B' and somthing else,
-- but not 'C'.
SELECT 2, 'A' UNION ALL
SELECT 2, 'B' UNION ALL
SELECT 2, 'D' UNION ALL
------- Customer #3 also meets the criteria.
-- Bought 'A' and 'B' and something else,
-- but not 'C'.
SELECT 3, 'A' UNION ALL
SELECT 3, 'B' UNION ALL
SELECT 3, 'D' UNION ALL
SELECT 3, 'A' UNION ALL
SELECT 3, 'D' UNION ALL
------- Customer #4 doesn't meet the criteria.
-- Bought 'A' and 'B' but also bought 'C'.
SELECT 4, 'A' UNION ALL
SELECT 4, 'B' UNION ALL
SELECT 4, 'C' UNION ALL
------- Customer #5 doesn't meet the criteria.
-- Bought 'A' and 'B' and something else,
-- but also bought 'C'.
SELECT 5, 'A' UNION ALL
SELECT 5, 'B' UNION ALL
SELECT 5, 'A' UNION ALL
SELECT 5, 'B' UNION ALL
SELECT 5, 'C' UNION ALL
SELECT 5, 'D' UNION ALL
------- Customer #6 doesn't meet the criteria.
-- Bought more than 1 of 'A' and something else
-- but not 'B'.
SELECT 6, 'A' UNION ALL
SELECT 6, 'A' UNION ALL
SELECT 6, 'D' UNION ALL
SELECT 6, 'E' UNION ALL
------- Customer #7 doesn't meet the criteria.
-- Bought more than 1 of 'B' and something else
-- but not 'A'.
SELECT 7, 'B' UNION ALL
SELECT 7, 'B' UNION ALL
SELECT 7, 'D' UNION ALL
SELECT 7, 'E'

go

declare @i int = 10;
while @i < 100000
begin
insert into #Purchase (CustomerID, ProductCode)
select CustomerID + @i, ProductCode + Left(ProductCode, 1)
From #Purchase
set @i = @i * 2
end

Then turn on statistics or open your SQL profiler
SET STATISTICS IO ON

And now you're ready.

Then you will also need an index on ProductCode.
Create Index IX_ProductCode On #Purchase (ProductCode) Include (CustomerID);

Post #1274898
Posted Thursday, March 29, 2012 2:23 AM
SSC Rookie

SSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC RookieSSC Rookie

Group: General Forum Members
Last Login: Friday, January 25, 2013 3:25 AM
Points: 27, Visits: 51
How about this? Although i agree query might get longer when there would be more than 3 items

 SELECT DISTINCT CustomerID
FROM #Purchase P
WHERE EXISTS (SELECT 1 FROM #Purchase P1
WHERE P.customerid = P1.customerid
AND P1.productcode = 'A'
)
AND EXISTS (SELECT 1 FROM #Purchase P2
WHERE P.customerid = P2.customerid
AND P2.productcode = 'B'
)
AND NOT EXISTS (SELECT 1 FROM #Purchase P3
WHERE P.customerid = P3.customerid
AND P3.productcode = 'C'
)

Post #1274924
« Prev Topic | Next Topic »

Add to briefcase 12345»»»

Permissions Expand / Collapse