Join All Elements in Python | Dataford Interview Questions

How to write a python script to join all elements of a list

Asked in the Coding Test stage. Round 2 coding test. For this SQL version, treat each list as a parent row and its elements as ordered child rows. Write a query that combines every element into one comma-separated value.

Output

One row per list, including lists without elements.
Columns: list_id, list_name, and joined_elements.
Preserve element position, use , as the delimiter, represent NULL elements as empty text, and order by list_id ascending.

Schema

lists

Column	Type	Description
list_idPK	INT	Unique identifier for the list
list_name	VARCHAR(100)	Name of the list

list_elements

Column	Type	Description
element_idPK	INT	Unique identifier for the element row
list_id	INT	List containing the element
position	INT	One-based position of the element in the list
element_value	VARCHAR(100)	Text value to join

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