How to remove duplicating rows from union statement - sql

Question

OK - I have looked and looked and found a lot of examples but nothing quite meeting my need. Maybe I used the wrong words to search with, but I could use your help. I will provide as much detail as I can.
I need to produce a report that merges fields from two tables, or rather a view and a table, into one table for a report. Here is the statement I am using:
SELECT A.ConfInt, A.Conference,
NULL as Ordered,
NULL as Approved,
NULL as PickedUp,
SUM(dbo.Case_Visit_Payments.Qty) AS Qty
FROM dbo.Conferences as A INNER JOIN
dbo.Case_Table ON A.ConfInt = dbo.Case_Table.Conference_ID INNER JOIN
dbo.Case_Visit_Payments ON dbo.Case_Table.Case_ID = dbo.Case_Visit_Payments.Case_ID
WHERE (dbo.Case_Visit_Payments.Item_ID = 15 AND A.ProjectCool = 1)
GROUP BY A.Conference, A.ConfInt
UNION
SELECT B.ConfInt,
B.Conference,
SUM(dbo.Cool_Fan_Order.NumberOfFansRequested) AS Ordered,
SUM(dbo.Cool_Fan_Order.Qty_Fans_Approved) AS Approved,
SUM(dbo.Cool_Fan_Order.Qty_Fans_PickedUp) AS PickedUp,
NULL AS Qty
FROM dbo.Conferences as B LEFT OUTER JOIN
dbo.Cool_Fan_Order ON B.ConfInt = dbo.Cool_Fan_Order.Conference_ID
where B.ProjectCool = 1
GROUP BY B.Conference, B.ConfInt
And here are the results:
4 Our Lady NULL NULL NULL 11
4 Our Lady 40 40 40 NULL
7 Holy Rosary 20 20 20 NULL
11 Little Flower NULL NULL NULL 21
11 Little Flower 5 5 20 NULL
19 Perpetual Help NULL NULL NULL 2
19 Perpetual Help 20 20 20 NULL
What I would strongly prefer is to not have the duplicating rows, such as:
4 Our Lady 40 40 40 11
7 Holy Rosary 20 20 20 NULL
11 Little Flower 5 5 20 21
19 Perpetual Help 20 20 20 2
I hope this question was clear enough. Any Suggestions would be greatly appreciated. And I do mark as answered. :)
Gregory

Answer 1

you could use your actual query as a subQuery, use an aggregate function (MAX OR SUM) on your non-duplicated values and group by the non aggregated columns
SELECT ConfInt, Conference, MAX(Ordered), MAX(Approved), MAX(PickedUp), MAX(Qty)
FROM (<your actualQuery>)
GROUP BY ConfInt, Conference.

Answer 2

The quick answer is to wrap your query inside another one,
SELECT ConfInt
, Conference
, SUM(Ordered) AS Ordered
, SUM(Approved) As Approved
, SUM(PickedUp) AS PickedUp
, SUM(Qty) AS Qty
FROM (
<your UNION query here>
)
GROUP BY ConfInt, Conference
This is not the only way to achieve the result set, but its the quickest fix to meet the specified requirements.
As an alternative, I believe these queries will return equivalent results:
We could use a correlated subquery in the SELECT list to get Qty:
;WITH q AS
( SELECT B.ConfInt
, B.Conference
, SUM(o.NumberOfFansRequested) AS Ordered
, SUM(o.Qty_Fans_Approved) AS Approved
, SUM(o.Qty_Fans_PickedUp) AS PickedUp
FROM dbo.Conferences as B
LEFT
JOIN dbo.Cool_Fan_Order o ON o.Conference_ID = B.ConfInt
WHERE B.ProjectCool = 1
GROUP BY B.ConfInt, B.Conference
)
SELECT q.ConfInt
, q.Conference
, q.Ordered
, q.Approved
, q.PickedUp
, ( SELECT SUM(v.Qty)
FROM dbo.Case_Table t
JOIN dbo.Case_Visit_Payments v ON v.Case_ID = t.Case_ID
WHERE t.Conference_ID = q.ConfInt
AND v.Item_ID = 15
) AS Qty
FROM q
ORDER BY q.ConfInt, q.Conference
Or, we could use LEFT JOIN operation on the two queries, rather than UNION. (We know that the query referencing Cool_Fan_Order can be the LEFT side of the outer join, because we know that it returns at least as many rows as the other query. (Basically, we know that the other query can't return values of ConfInt and Conference that aren't in the Cool_Fan_Order query.)
;WITH p AS
( SELECT A.ConfInt
, A.Conference
, SUM(v.Qty) AS Qty
FROM dbo.Conferences as A
JOIN dbo.Case_Table t ON t.Conference_ID = A.ConfInt
JOIN dbo.Case_Visit_Payments v ON v.Case_ID = t.Case_ID
WHERE A.ProjectCool = 1
AND v.Item_ID = 15
GROUP BY A.ConfInt, A.Conference
)
, q AS
( SELECT B.ConfInt
, B.Conference
, SUM(o.NumberOfFansRequested) AS Ordered
, SUM(o.Qty_Fans_Approved) AS Approved
, SUM(o.Qty_Fans_PickedUp) AS PickedUp
FROM dbo.Conferences as B
LEFT
JOIN dbo.Cool_Fan_Order o ON B.ConfInt = o.Conference_ID
WHERE B.ProjectCool = 1
GROUP BY B.ConfInt, B.Conference
)
SELECT q.ConfInt
, q.Conference
, q.Ordered
, q.Approved
, q.PickedUp
, p.Qty
FROM q
LEFT
JOIN p ON p.ConfInt = q.ConfInt AND p.Conference = q.Conference
ORDER BY q.ConfInt, q.Conference
The choice between those three (they all return an equivalent resultset under all conditons), boils down to readability and maintainability, and performance. On large enough rowsets, there may be some observable performance differences between the three statements.

Answer 3

I'd just put the join to Cool_Fan_Order in the first select and remove the union.
Does this return the same results?
select
A.ConfInt,
A.Conference,
sum(dbo.Cool_Fan_Order.NumberOfFansRequested) as Ordered,
sum(dbo.Cool_Fan_Order.Qty_Fans_Approved) as Approved,
sum(dbo.Cool_Fan_Order.Qty_Fans_PickedUp) as PickedUp,
sum(sub.Qty) as Qty
from
dbo.Conferences as A
left outer join
(
select
c.ConfInt,
cvp.Qty
from dbo.Conferences c
inner join dbo.Case_Table ct
on a.confInt=ct.Conference_ID
inner join dbo.Case_Visit_Payments cvp
on ct.Case_ID=cvp.Case_ID
where cvp.Item_ID=15
) sub
on a.ConfInt=sub.ConfInt
left outer join dbo.Cool_Fan_Order
on A.ConfInt = dbo.Cool_Fan_Order.Conference_ID
where
(
A.ProjectCool = 1
)
group by
A.Conference,
A.ConfInt