Getting a summary report based on grouping 2 user IDs - sql

Question

I have a table as such:
MsgID MsgrUserID MsgdUserID MsgDate Message
1 1 4 6/12/2015 Jules - Did you pick up the blueprints?
2 4 1 6/15/2015 Yes, they're in my hands
3 4 1 6/15/2015 Let me know when you can talk
4 3 4 6/16/2015 Jules, let's meet tomorrow
5 1 4 6/17/2015 I'm available at 2 PM today
6 1 3 7/4/2015 Cindy, did you check your mail?
7 4 3 7/3/2015 OK, I'm free after 3PM
8 3 1 7/2/2015 Yes, there was nothing there
9 2 1 7/5/2015 Plan is going well. Just need more time
10 1 2 7/5/2015 OK, great. Let me know
What I need to do is get a report that sums up all of the correspondence. It would look something like this:
User: 1
Correspondence between you and 2: 2 Last correspondence: 7/5/2015
Correspondence between you and 3: 2 Last correspondence: 7/4/2015
Correspondence between you and 4: 4 Last correspondence: 6/17/2015
Or something like that. So, I need to figure out how to sum the number of correspondence, but also get other pieces of information from the original table. The problem I'm having is that I can't figure out how to link the sum to the original table, because it's conditional. Sometimes the user's ID is in the Msgr (Messenger) field, and sometimes it's in the Msgd (Messaged) field.
I've got this monster, but I know the join to #MyMsgs table is where the error lies.
with cte as (
select
MessagedUserID as MessagedUserIDOrig,
MessagerUserID as MessagerUserIDOrig,
case when MessagerUserID < MessagedUserID
then MessagerUserID else MessagedUserID end MessagerUserID,
case when MessagerUserID > MessagedUserID
then MessagerUserID else MessagedUserID end MessagedUserID
from tmpMessaged
)
select MessagerUserID, MessagedUserID, count(*) as Contact
into #MyMsgs
from cte
WHERE MessagerUserID = #MyID
OR MessagedUserID = #MyID
group by MessagerUserID, MessagedUserID
SELECT
T1.*,
Mgr.UserName as MessagerName,
Mgr.UserID as UserID,
CASE WHEN T1.MessagedUserID = #MyID THEN Mgd.UserImg1 ELSE Mgr.UserImg1 END as UserImg1,
Mgd.UserName as MessagedName,
CC.Contact,
Mgd.LastLoginDate as LastOnline,
CASE WHEN T1.MessagedUserID = #MyID THEN 'Received' ELSE 'Sent' END as LContact,
LEFT(T1.[Message], 100) + '...' as [uMessage],
CASE WHEN T1.MessageViewed IS NULL THEN 'No' ELSE 'Yes' END as MsgViewed,
CASE WHEN T1.MessageFlag IS NULL THEN 'No' ELSE 'Yes' END as MsgFlagged
FROM [dbo].[tmpMessaged] T1
LEFT JOIN [dbo].[tmpUsers] Mgr
ON T1.[MessagerUserID] = Mgr.[UserID]
LEFT JOIN [dbo].[tmpUsers] Mgd
ON T1.[MessagedUserID] = Mgd.[UserID]
LEFT JOIN [dbo].[tmpMessaged] T2
ON T1.MessageID = T2.MessageID
LEFT JOIN #MyMsgs CC
ON CASE
-- WHEN T1.MessagerUserID = #MyID AND CC.MessagerUserID = T1.MessagerUserID THEN 1
WHEN T1.MessagedUserID = #MyID AND CC.MessagedUserID = T1.MessagedUserID THEN 1
ELSE 0
END = 1
WHERE
-- First grab the records where the User's ID is in the Messaged field
Mgd.[UserID] = #MyID
UNION
SELECT
T1.*,
Mgr.UserName as MessagerName,
Mgr.UserID as UserID,
CASE WHEN T1.MessagerUserID = #MyID THEN Mgr.UserImg1 ELSE Mgd.UserImg1 END as UserImg1,
Mgd.UserName as MessagedName,
CC.Contact,
Mgd.LastLoginDate as LastOnline,
CASE WHEN T1.MessagerUserID = #MyID THEN 'Sent' ELSE 'Received' END as LContact,
LEFT(T1.[Message], 100) + '...' as [uMessage],
CASE WHEN T1.MessageViewed IS NULL THEN 'No' ELSE 'Yes' END as MsgViewed,
CASE WHEN T1.MessageFlag IS NULL THEN 'No' ELSE 'Yes' END as MsgFlagged
FROM [dbo].[tmpMessaged] T1
LEFT JOIN [dbo].[tmpUsers] Mgr
ON T1.[MessagerUserID] = Mgr.[UserID]
LEFT JOIN [dbo].[tmpUsers] Mgd
ON T1.[MessagedUserID] = Mgd.[UserID]
LEFT JOIN [dbo].[tmpMessaged] T2
ON T1.MessageID = T2.MessageID
LEFT JOIN #MyMsgs CC
ON CASE
WHEN T1.MessagerUserID = #MyID AND CC.MessagerUserID = T1.MessagerUserID THEN 1
-- WHEN T1.MessagedUserID = #MyID AND CC.MessagerUserID = T1.MessagedUserID THEN 1
ELSE 0
END = 1
WHERE
-- Now grab the records where the User's ID is in the Messager field
Mgr.[UserID] = #MyID
ORDER BY T1.MessageDate DESC

Answer 1

You could just do the aggregation directly in the common table expression:
declare #myID int = 1;
with cte as (
select
case when MessagerUserID < MessagedUserID
then MessagerUserID else MessagedUserID end MessagerUserID,
case when MessagerUserID > MessagedUserID
then MessagerUserID else MessagedUserID end MessagedUserID,
count(*) MessageCount,
max(MessageDate) LastMessageDate
from tmpMessaged
group by
case when MessagerUserID < MessagedUserID
then MessagerUserID else MessagedUserID end,
case when MessagerUserID > MessagedUserID
then MessagerUserID else MessagedUserID end
)
select * from cte where MessagerUserID = #myID;
With your sample data this would result in:
MessagerUserID MessagedUserID MessageCount LastMessageDate
-------------- -------------- ------------ ---------------
1 2 2 2015-07-05
1 3 2 2015-07-04
1 4 4 2015-06-17
The specific formatting with headers/details etc is probably better to do in the actual reporting application, although it's certainly possibly to do directly on the server too (but who uses SSMS for pretty reports anyway).

Answer 2

I asked about the sender ever being the receiver and got the answer I hoped for (no). With that rule in place, you can "cheat" and double-stack the records, swapping participant 1 and participant 2 in half of them, then only concern yourself with selecting from that structure and treating participant 1 as "your guy" and participant 2 as "other guy". You'll never double-count a record when sender cannot ever equal receiver.
DECLARE #UserYouCareAbout int
SET #UserYouCareAbout = 1
SELECT CONVERT(nvarchar(max), GETDATE(), 101)
SELECT
'Correspondence between you and ' + CONVERT(nvarchar(max), [Message Participant 2]) + ': ' + STR(MAX(MsgDate), 4, 0) AS [Conversation With],
'Last correspondence: ' + CONVERT(nvarchar(max), MAX(MsgDate), 101) AS [Last Communication]
/*
--individual unformatted pieces
,
COUNT(MsgID) AS [MessageCount],
[Message Participant 2] AS [Other Guy],
MAX(MsgDate) AS [LastDate]
*/
FROM
(
(
SELECT
MsgID,
MsgrUserID AS [Message Participant 1],
MsgdUserID AS [Message Participant 2],
MsgDate
FROM
tmpMessaged
) --SentStuff
UNION ALL
(
SELECT
MsgID,
MsgdUserID AS [Message Participant 1], --note that
MsgrUserID AS [Message Participant 2], --these switched
MsgDate
FROM
tmpMessaged
) --RecStuff
) DerivedAllMessagesTwice
WHERE
[Message Participant 1] = #UserYouCareAbout
GROUP BY
[Message Participant 2]
This simplification eliminates all of the inline conditionals.

Answer 3

Try the following code :-
declare #MyID int = 1
create table #yourmsgtable (MsgID int, MsgrUserID int, MsgdUserID int, MsgDate date, Message varchar(max))
insert into #yourmsgtable values
(1,1,4,'6/12/2015','Jules - Did you pick up the blueprints?'),
(2,4,1,'6/15/2015','Yes, they''re in my hands'),
(3,4,1,'6/15/2015','Let me know when you can talk'),
(4,3,4,'6/16/2015','Jules, let''s meet tomorrow'),
(5,1,4,'6/17/2015','I''m available at 2 PM today'),
(6,1,3,'7/4/2015','Cindy, did you check your mail?'),
(7,4,3,'7/3/2015','OK, I''m free after 3PM'),
(8,3,1,'7/2/2015','Yes, there was nothing there'),
(9,2,1,'7/5/2015','Plan is going well. Just need more time'),
(10,1,2,'7/5/2015','OK, great. Let me know')
create table #tmpmsgtable(party1 int, party2 int, msgdate date)
insert into #tmpmsgtable
select MsgrUserID, MsgdUserID, MsgDate from #yourmsgtable where MsgrUserID = #MyID
union all
select MsgdUserID, MsgrUserID, MsgDate from #yourmsgtable where MsgdUserID = #MyID
select
'User : ' + convert(varchar(max),party1) 'Party 1',
'Correspondence between you and ' + convert(varchar(max),party2) + ' : ' + convert(varchar(max),count(*)) 'Party 2 Correspondence',
'Last correspondence : ' + convert(nvarchar(max),max(msgdate)) 'Last correspondence'
from #tmpmsgtable
group by party1, party2
drop table #tmpmsgtable
drop table #yourmsgtable
Result :-