oracle 12c listagg使用串联的字段值

Question

Using NVL2 to concatenate two fields, the following returns correct data.

 select mi2.item_id,
     nvl2(mipp2.serial_number, mipp2.serial_number||'-', null)
     ||nvl2(prod2.code, '' ||prod2.code, null) as green_code
           from store_item mi2
           join store_item_products mipp2
             on mi2.store_item_id = mipp2.store_item_id
           join product prod2 
             on mipp2.product_id = prod2.id 

What I now need to do is use the green_code data, all within one statement, within a listagg function to gather multiple green_code values within single item_Id values

everything I have tried is returning piles of 'NULL' values and not properly listing the concatenated green_code values.

There are just under fifty additional fields, from these same and eight additional tables, that need to be returned by the single SQL statement (into a view), so I am trying to stay away from having to list all fields into the group by statement.

Any help with the syntax to gather the above listed concatenated field (green_code) into a listagg function within single item_Id values will be greatly appreciated....

Answer 1

I may not be correct because what you need to fulfill is not clear. But using a sub query is all what you need it seems. Syntax may be wrong but hope you can get the idea. eg :

SELECT item_id, listagg(green_code, ',') WITHIN GROUP (ORDER BY green_code) as green_code_list 
FROM (select mi2.item_id item_id,
     nvl2(mipp2.serial_number, mipp2.serial_number||'-', null)
     ||nvl2(prod2.code, '' ||prod2.code, null) as green_code
           from store_item mi2
           join store_item_products mipp2
             on mi2.store_item_id = mipp2.store_item_id
           join product prod2 
             on mipp2.product_id = prod2.id )
GROUP BY item_id;