Category Breadcrumbs for Leaf Nodes

SQL practice question · Hard · Recursive & Hierarchy · Google, Flipkart

`shopping_categories` is a category tree (`parent_id` NULL for top-level categories). For every LEAF category (one that is nobody's parent) build its breadcrumb from the top: names joined with ' > ' (e.g. 'Electronics > Audio > Headphones'). Return `cat_id`, `breadcrumb`, `depth` (top level = 1). Order by `breadcrumb`.

Table: shopping_categories

Schema of shopping_categories
ColumnType
cat_idINTEGER
parent_idINTEGER
cat_nameTEXT
Sample rows of shopping_categories
cat_idparent_idcat_name
1NULLElectronics
21Audio
32Headphones
42Speakers
51Cameras
6NULLHome
76Kitchen
Expected output on the sample data
cat_idbreadcrumbdepth
3Electronics > Audio > Headphones3
4Electronics > Audio > Speakers3
5Electronics > Cameras2
7Home > Kitchen2

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