SQL: get latest (un)subscribeaction from table - sql

Question

I have the following table:
ID (int)
EMAIL (varchar(50))
CAMPAIGNID (int)
isSubscribe (bit)
isActionByUser (bit)
This table stores all subscribe and unsubscribe actions on campaigns for a user. These actions can be done by the user itself (isActionByUser = true) or by the administration desk (isActionByUser = false).
I need to get the last action to determine if a user is subscribed or unsubscribed. But keeping in mind that when a user did an unsubscribe action from a campaign, it will have priority on other subscribe actions by the administration desk.
I have found a nice solution to get the lastest record grouped by EMAIL and CAMPAIGNID. But I can't figure out how I do incorporate the requirement that an isActionByUser = true, has absolute priority over records with isActionByUser = false.
Also: when the administration desk does an unsubscribe action, it will have priority over a record with (isSubscribe = true and isActionByUser).
Example data:
ID EMAIL CAMPAIGNID ISSUBSCRIBE ISACTIONBYUSER
-----------------------------------------------------------
1 a#aa.com 1 1 0
2 b#bb.com 1 1 0
3 c#cc.com 1 1 0
4 a#aa.com 1 0 1
5 a#aa.com 1 1 0
6 c#cc.com 1 1 1
7 c#cc.com 1 0 0
The expected result would be:
ID EMAIL CAMPAIGNID ISSUBSCRIBE ISACTIONBYUSER
-----------------------------------------------------------
2 b#bb.com 1 1 0
4 a#aa.com 1 0 1
7 c#cc.com 1 0 0
With the following query
select cs1.*
from
[TABLE] cs1
left join
[TABLE] cs2
on
cs1.EM_EMAIL = cs2.EM_EMAIL
and
cs1.EM_CAMPAIGNID = cs2.EM_CAMPAIGNID
and
cs1.id < cs2.id
where cs2.id is null
I' m having the following result:
ID EMAIL CAMPAIGNID ISSUBSCRIBE ISACTIONBYUSER
-----------------------------------------------------------
2 b#bb.com 1 1 0
5 a#aa.com 1 1 0
7 c#cc.com 1 0 0
Another approach:
SELECT *
FROM [TABLE] cs
WHERE id in
(
SELECT top 1 id
FROM [TABLE] ss
WHERE
cs.EMAIL = ss.EMAIL
and
cs.CAMPAIGNID = ss.CAMPAIGNID
and ISSUBSCRIBE = (
select top 1 min(convert(int, ISSUBSCRIBE))
FROM [TABLE] sss
WHERE
cs.EMAIL = sss.EMAIL
and
cs.CAMPAIGNID = sss.CAMPAIGNID
)
and ISACTIONBYUSER= (
select top 1 max(convert(int, ISACTIONBYUSER))
FROM [TABLE] ssss
WHERE
cs.EMAIL = ssss.EMAIL
and
cs.CAMPAIGNID = ssss.CAMPAIGNID
)
)
This will produce the following result:
ID EMAIL CAMPAIGNID ISSUBSCRIBE ISACTIONBYUSER
-----------------------------------------------------------
2 b#bb.com 1 1 0
4 a#aa.com 1 0 1
6 c#cc.com 1 1 1
Which is also not correct. And I'm afraid performance will be a big rpoblem with this approach.
So any ideas how I can solve this?

Answer 1

Ok, try the following query:
SELECT DISTINCT B.*
FROM YourTable A
OUTER APPLY (SELECT TOP 1 *
FROM YourTable
WHERE Email = A.Email AND CampaignId = A.CampaignId
ORDER BY CASE WHEN ISSUBSCRIBE = 0 THEN 1 ELSE 2 END,
CASE WHEN ISACTIONBYUSER = 1 THEN 1 ELSE 2 END,
ID DESC) B

Answer 2

Try this: [Updated to handle unsubscribe and subscribed users]
declare #test table (id int, email varchar(100), CAMPAIGNID int, ISSUBSCRIBE bit, ISACTIONBYUSER bit)
INSERT INTO #test
SELECT 1,'a#aa.com',1,1,0 UNION
SELECT 2,'b#bb.com',1,1,0 UNION
SELECT 3,'c#cc.com',1,1,0 UNION
SELECT 4,'a#aa.com',1,0,1 UNION
SELECT 5,'a#aa.com',1,1,0 UNION
SELECT 6,'c#cc.com',1,1,1 UNION
SELECT 7,'c#cc.com',1,0,0 UNION
select 8, 'd#dd.com', 1, 1, 1 UNION
select 9, 'd#dd.com', 1, 0, 1 UNION
select 10, 'd#dd.com', 1, 1, 1
;WITh CTE AS
(
select s.*,
ROW_NUMBER() OVER (PARTITION BY email,campaignid
ORDER BY
case
when ISSUBSCRIBE = 0 AND ISACTIONBYUSER = 0 THEN 1
when ISSUBSCRIBE = 0 AND ISACTIONBYUSER = 1 THEN 1
when ISSUBSCRIBE = 1 AND ISACTIONBYUSER = 1 THEN 1 ELSE 2 END, ID DESC) Rn1
from #test s
)
SELECT * FROM CTE WHERE Rn1 = 1
order by id

Answer 3

This is some standard SQL that might get you there, though it's not the prettiest ever:
Updated:
select s.*
from Subscriptions s
join (
-- Apply the user unsubscribe logic to get the proper ID
select case when b.ID is not null and a.ISACTIONBYUSER = 0 then b.ID else a.ID end as ID
from (
-- Latest overall
select ID, EMAIL, CAMPAIGNID,
(select ISACTIONBYUSER from Subscriptions where ID = z.ID) as ISACTIONBYUSER
from (
select max(ID) as ID, EMAIL, CAMPAIGNID
from Subscriptions a
group by EMAIL, CAMPAIGNID
) as z
) as a
left join (
-- Latest user unsubscribe
select max(ID) as ID, EMAIL, CAMPAIGNID, 1 as ISACTIONBYUSER
from Subscriptions
where ISSUBSCRIBE = 0
and ISACTIONBYUSER = 1
group by EMAIL, CAMPAIGNID
) as b on a.EMAIL = b.EMAIL
and a.CAMPAIGNID = b.CAMPAIGNID
) as i on s.ID = i.ID
I've updated this to account for this case:
insert into Subscriptions select 8, 'd#dd.com', 1, 1, 1
insert into Subscriptions select 9, 'd#dd.com', 1, 0, 1
insert into Subscriptions select 10, 'd#dd.com', 1, 1, 1