Oracle SQL Columns to Rows without UNPIVOT - sql

Question

What I currently have:
Team User Apples Oranges Pears
Red Adam 4 5 6
Red Avril 11 12 13
Blue David 21 22 23
What's needed:
Team User Product Count
Red Adam Apples 4
Red Adam Oranges 5
Red Adam Pears 6
Red Avril Apples 11
Red Avril Oranges 12
Red Avril Pears 13
Blue David Apples 21
....
This is to be implemented using Oracle SQL. I understand this can be done using UNPIVOT, but my Oracle SQL version is too old to support this method. Can someone provide an example of how to achieve this using CROSS APPLY or equivalent methods? Count changes depending on team-user-product combination, and the number of product types may change slightly in the future so a scalable solution might be necessary.
This is time-sensitive, so I appreciate the help.

Answer 1

You can do this using a cross join and some case statements by using a dummy subquery that holds the same number of rows as you have columns that you want to unpivot (since you want each column to go into its own row) like so:
WITH your_table AS (SELECT 'Red' Team, 'Adam' usr, 4 Apples, 5 Oranges, 6 Pears FROM dual UNION ALL
SELECT 'Red' Team, 'Avril' usr, 11 Apples, 12 Oranges, 13 Pears FROM dual UNION ALL
SELECT 'Blue' Team, 'David' usr, 21 Apples, 22 Oranges, 23 Pears FROM dual)
-- end of mimicking your table. See SQL below:
SELECT yt.team,
yt.usr,
CASE WHEN d.id = 1 THEN 'Apples'
WHEN d.id = 2 THEN 'Oranges'
WHEN d.id = 3 THEN 'Pears'
END product,
CASE WHEN d.id = 1 THEN yt.apples
WHEN d.id = 2 THEN yt.oranges
WHEN d.id = 3 THEN yt.pears
END count_of_product
FROM your_table yt
CROSS JOIN (SELECT LEVEL ID
FROM dual
CONNECT BY LEVEL <= 3) d -- number of columns to unpivot
ORDER BY team, usr, product;
TEAM USR PRODUCT COUNT_OF_PRODUCT
---- ----- ------- ----------------
Blue David Apples 21
Blue David Oranges 22
Blue David Pears 23
Red Adam Apples 4
Red Adam Oranges 5
Red Adam Pears 6
Red Avril Apples 11
Red Avril Oranges 12
Red Avril Pears 13
Doing it this way means that you only have to go through the table once, rather than multiple times if you were doing the union all method.
ETA: Here's the method that Aleksej was referring to - I would suggest testing both methods against your set of data (which is hopefully large enough to be representative) to see which one is more performant:
WITH your_table AS (SELECT 'Red' Team, 'Adam' usr, 4 Apples, 5 Oranges, 6 Pears FROM dual UNION ALL
SELECT 'Red' Team, 'Avril' usr, 11 Apples, 12 Oranges, 13 Pears FROM dual UNION ALL
SELECT 'Blue' Team, 'David' usr, 21 Apples, 22 Oranges, 23 Pears FROM dual)
-- end of mimicking your table. See SQL below:
SELECT yt.team,
yt.usr,
CASE WHEN LEVEL = 1 THEN 'Apples'
WHEN LEVEL = 2 THEN 'Oranges'
WHEN LEVEL = 3 THEN 'Pears'
END product,
CASE WHEN LEVEL = 1 THEN yt.apples
WHEN LEVEL = 2 THEN yt.oranges
WHEN LEVEL = 3 THEN yt.pears
END count_of_product
FROM your_table yt
CONNECT BY PRIOR team = team
AND PRIOR usr = usr
AND PRIOR sys_guid() IS NOT NULL
AND LEVEL <= 3
ORDER BY team, usr, product;
TEAM USR PRODUCT COUNT_OF_PRODUCT
---- ----- ------- ----------------
Blue David Apples 21
Blue David Oranges 22
Blue David Pears 23
Red Adam Apples 4
Red Adam Oranges 5
Red Adam Pears 6
Red Avril Apples 11
Red Avril Oranges 12
Red Avril Pears 13

Answer 2

You can use a big union all like this:
select
Team,
"User",
'Apples' Product,
Apples "Count"
from your_table
union all
select
Team,
"User",
'Oranges' Product,
Oranges "Count"
from your_table
union all
select
Team,
"User",
'Pears' Product,
Pears "Count"
from your_table
union all
. . .
Also, try not to use keywords such as User or Count as identifiers or else, wrap them in double quotes like I did.