Using Pivot or CTE to horizontalize a query - sql

Question

I am using sql 2008
My data set looks like
Entity Type1 Type2 Balance
1 A R 100
1 B Z 200
1 C R 300
2 A X 1000
2 B Y 2000
My output should look like
Entity A-Type2 A-Balance B-Type2 B-Balance C-Type2 C-Balance
1 R 100 Z 200 R 300
2 X 1000 Y 2000 0
Now I started writing a pivot query, and I think I can get away with MAX because there should be one record per Entity/Type1 combination. But can not figure out how to do two fields in one pivot. Is this possible? Is this something that CTE could help out with?

Answer 1

Easiest is the MAX idea, but with a CASE statement, e.g.:
SELECT
Entity,
MAX(CASE WHEN Type1 = 'A' THEN Type2 ELSE NULL END) AS AType2,
MAX(CASE WHEN Type1 = 'A' THEN Balance ELSE NULL END) AS ABalance,
MAX(CASE WHEN Type1 = 'B' THEN Type2 ELSE NULL END) AS BType2,
MAX(CASE WHEN Type1 = 'B' THEN Balance ELSE NULL END) AS BBalance,
MAX(CASE WHEN Type1 = 'C' THEN Type2 ELSE NULL END) AS CType2,
MAX(CASE WHEN Type1 = 'C' THEN Balance ELSE NULL END) AS CBalance
FROM
...
GROUP BY
Entity
In other words, only use the value when Type1 is a specific value (with other Type1 values getting a null).

Answer 2

You just use conditional aggregation for the pivoting like this:
select Entity,
max(case when Type1 = 'A' then Type2 end) as A_Type2,
max(case when Type1 = 'A' then Balance else 0 end) as A_Balance,
max(case when Type1 = 'B' then Type2 end) as B_Type2,
max(case when Type1 = 'B' then Balance else 0 end) as B_Balance,
max(case when Type1 = 'C' then Type2 end) as C_Type2,
max(case when Type1 = 'C' then Balance else 0 end) as C_Balance
from MyDataSet mds
group by Entity;

Answer 3

Here's doing it with a pivot and a lookup.
SELECT
data.Entity,
ISNULL(a.Type2,'') AS [A-Type2],
ISNULL([A-Balance],0) AS [A-Balance],
ISNULL(b.Type2,'') AS [B-Type2],
ISNULL([B-Balance],0) AS [B-Balance],
ISNULL(c.Type2,'') AS [C-Type2],
ISNULL([C-Balance],0) AS [C-Balance]
FROM
(
SELECT
Entity,
A AS [A-Balance],
B AS [B-Balance],
C AS [C-Balance]
FROM
(
SELECT Entity, Type1, Balance FROM #table
) t
PIVOT (
MAX(Balance)
FOR Type1 IN ([A],[B],[C])
) piv
) data
LEFT OUTER JOIN #table a on a.Type1 = 'A'
AND a.Entity = data.Entity AND a.Balance = [A-Balance]
LEFT OUTER JOIN #table b on b.Type1 = 'B'
AND b.Entity = data.Entity AND b.Balance = [B-Balance]
LEFT OUTER JOIN #table c on c.Type1 = 'C'
AND c.Entity = data.Entity AND c.Balance = [C-Balance]