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Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Duplicate numbers aren't tested.
In the description, it´s unclear from where to retrive data (table schema - numbers), and also the output schema (in the graphic seems that column should be integer and it is n).
Duplicate: https://www.codewars.com/kata/59fca81a5712f9fa4700159a/
Rows are not guaranteed to be fetched in any particular order.