Question

My dataset is not exactly like EAV format, but it’s somewhat similar; here’s the data:

In the format I need is as follows:

For every EN_NO group I need the data in above format. If group on EN_NO > 1 then respestive product key should go to respestive product column otherwise not (for e.g. EN_NO 4 and 5).

I hope I am clear. Data is in a Qracle table, please suggest a query to get the data in the format I need.

Thanks,
Prakash

Answer 1

I would highly recommend altering your table structure. At present you have two pieces of information tied into a single field. This is a SQL Anti-Pattern and destroys the ability of Oracle to user certain optimisations.

Instead, please consider splitting “PROD_KEY” into two fields (PRODUCT_TYPE = Prod_A, etc) (SUB_PRODUCT_ID = 1, 2, 3, etc). Or, to cause less potential change across the database, simply add the PRODUCT_TYPE to your current table.

That said, using your current structure…

SELECT
  EN_NO,
  PROD_KEY,
  CASE WHEN (EN_NO < 4) AND (LEFT(PROD_KEY, 6) = 'Prod_A') THEN PROD_KEY ELSE NULL END AS Prod_A,
  CASE WHEN (EN_NO < 4) AND (LEFT(PROD_KEY, 6) = 'Prod_B') THEN PROD_KEY ELSE NULL END AS Prod_B,
  CASE WHEN (EN_NO < 4) AND (LEFT(PROD_KEY, 6) = 'Prod_C') THEN PROD_KEY ELSE NULL END AS Prod_C,
  PROD_QTY
FROM
  yourTable

This works when you know specifically what columns you need as output. If you need the code to adapt to having Prod_D, etc, then you need to write code that writes code (Dynamic SQL).