Question

I have a legacy table whos data I have to migrate to a new structure. In the old structure each row represesnts an year, having fields for each month. In the new one each row will represent a month. The old structure is :

OLD_TABLE (
id1,
id2,
    year,
price01,
price02,
price03,
price04,
...
price11,
price12,
quantity01,
quantity02,
quantity03,
...
quantity11,
quantity12,

) -> PK = id1,id2,year

the new structure is like this :

NEW_TABLE (
id1,
id2,
year,
month,
quantity,
price,

) -> PK = id1,id2, year

Any advices on how should i proceed in migrating data from the old structure to the new one?

Thank you!

Answer 1

If you are using 11g or later, look at the unpivot syntax

Something like…

SELECT *
FROM yourtable
UNPIVOT (price FOR pmonth IN (price01 AS 1, price02 AS 2...))
UNPIVOT (quantity FOR qmonth IN (quantity01 AS 1, quantity02 AS 2...))
WHERE pmonth=qmonth