SQL Update query product cart - sql

Question

ID ProductId MemberId SessionId CreatedOn Quantity
62 1 2 2012-09-11 1
63 2 2 2012-09-11 1
64 1 0 agzdeoqubwokfme05wwmne55 2012-09-11 1
65 3 0 agzdeoqubwokfme05wwmne55 2012-09-11 1
I have above table and I need to make one procedure.
My scenario is without login add item to cart and when you login merge all items.
I will pass two parameter in procedure #MemberId (Login Member Id), #SessionID
And I want out put table like below.
ID ProductId MemberId SessionId CreatedOn Quantity
62 1 2 2012-09-11 2
63 2 2 2012-09-11 1
65 3 2 2012-09-11 1
One product merges with another product and makes quantity 2. And that row should be gone.

Answer 1

Assuming SQL SERVER 2005 or above
CREATE TABLE #T (ID INT , ProductId INT, MemberId INT, SessionId VARCHAR(100), CreatedOn DATETIME, Quantity INT)
INSERT INTO #T SELECT 62,1 ,2 ,' ','2012-09-11',1
INSERT INTO #T SELECT 63, 2,2, ' ','2012-09-11',1
INSERT INTO #T SELECT 64, 1,0,'agzdeoqubwokfme05wwmne55','2012-09-11',1
INSERT INTO #T SELECT 65, 3,0,'agzdeoqubwokfme05wwmne55','2012-09-11',1
;With CTE AS
(SELECT
ID
,ProductId
,MemberId = MAX(MemberId) OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
,SessionID
,CreatedOn = CONVERT(VARCHAR(10),MAX(CreatedOn) OVER(PARTITION BY ProductID ORDER bY(SELECT 1)),20)
,Quantity = SUM(Quantity) OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
,Rn = ROW_NUMBER() OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
FROM #T)
SELECT ID,ProductId,MemberId,SessionID,CreatedOn,Quantity FROM CTE WHERE Rn = 1
DROP TABLE #T
will give the result as
ID ProductId MemberId SessionID CreatedOn Quantity
62 1 2 2012-09-11 2
63 2 2 2012-09-11 1
65 3 0 agzdeoqubwokfme05wwmne55 2012-09-11 1
Finally if you want to update the table, the here you go
UPDATE #T
SET
#T.ID = c.ID
,#T.ProductId =c.ProductId
,#T.MemberId = c.MemberId
,#T.SessionID = c.SessionID
,#T.CreatedOn = c.CreatedOn
,#T.Quantity = c.Quantity
FROM #T
INNER JOIN CTE c
ON #T.ID = c.ID
WHERE c.Rn = 1
The result is
ID ProductId MemberId SessionId CreatedOn Quantity
62 1 2 2012-09-11 2
63 2 2 2012-09-11 1
64 1 0 agzdeoqubwokfme05wwmne5 2012-09-11 1
65 3 0 agzdeoqubwokfme05wwmne55 2012-09-11 1
The complete query is
;With CTE AS
(SELECT
ID
,ProductId
,MemberId = MAX(MemberId) OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
,SessionID
,CreatedOn = CONVERT(VARCHAR(10),MAX(CreatedOn) OVER(PARTITION BY ProductID ORDER bY(SELECT 1)),20)
,Quantity = SUM(Quantity) OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
,Rn = ROW_NUMBER() OVER(PARTITION BY ProductID ORDER bY(SELECT 1))
FROM #T)
UPDATE #T
SET
#T.ID = c.ID
,#T.ProductId =c.ProductId
,#T.MemberId = c.MemberId
,#T.SessionID = c.SessionID
,#T.CreatedOn = CONVERT(VARCHAR(10),c.CreatedOn,20)
,#T.Quantity = c.Quantity
FROM #T
INNER JOIN CTE c
ON #T.ID = c.ID
WHERE c.Rn = 1
SELECT * FROM #T
DROP TABLE #T
For Any Version of SQL
UPDATE #T
SET
#T.ID = c.ID
,#T.ProductId =c.ProductId
,#T.MemberId = c.MemberId
,#T.SessionID = c.SessionID
,#T.CreatedOn = c.CreatedOn
,#T.Quantity = c.Quantity
FROM #T
INNER JOIN (SELECT t.ID,t.ProductID,t.MemberId,t.SessionId,t.CreatedOn,x.Quantity
FROM #T t
JOIN (
SELECT
ID = MIN(ID)
,ProductID
,MemberId = MAX(MemberId)
,CreatedOn = MAX(CreatedOn)
,Quantity = SUM(Quantity)
FROM #T
GROUP BY ProductID
)X
ON t.ID =X.ID) c
ON #T.ID = c.ID
SELECT * FROM #T
DROP TABLE #T

Answer 2

SELECT ProductID,
max(MemberId),
max(CreatedOn),
sum(Quantity)
FROM theTable
WHERE SessionID=<id> or MemberID=<id>
GROUP BY ProductID

Answer 3

Updating may not be the optimum solution, it may be better to delete all the records and insert new ones.
Anyhow you need to do something like this if you want to update and then delete the extra ones.
Assuming ID is the unique key here. Here is complete logic, read carefully
DECLARE #Temp1 TABLE
(
--datafields same AS your table
)
DECLARE #Temp2 TABLE
(
--datafields same AS your table
)
INSERT INTO #Temp1
SELECT ID,
ProductID,
MemberId,
SessionId,
CreatedOn,
Quantity
FROM theTable
WHERE SessionID= #SessionID or MemberID= #MemberID
UPDATE a
SET SessionID = #SessionID , MemberID= #MemberID
FROM #Temp1 AS a
--WHERE SessionID= #SessionID OR MemberID= #MemberID
INSERT INTO #Temp2
SELECT MAX(ID),
ProductID,
max(MemberId),
MAX(SessionId),
max(CreatedOn),
sum(Quantity)
FROM #Temp1
GROUP BY ProductID
UPDATE a
SET a.MemberId = b.MemberId ,a.SessionId=b.SessionId ,a.CreatedOn=b.CreatedOn,a.Quantity=b.Quantity
FROM YourTable AS a
INNER JOIN #Temp2 AS b
ON a.ID=b.ID
DELETE FROM YourTable
WHERE ID IN ( SELECT ID
FROM #Temp1 AS ta
WHERE NOT EXISTS ( SELECT 1
FROM #Temp2 AS tb
WHERE ta.ID = tb.ID ) )