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#0376
Product Share Within Category
MediumSQL24 min20 XP
Problem
Return category, product, revenue, and category_share.
Why This Matters
SQL interviews usually test whether you can turn a business question into the right rows, grouping level, join type, and edge-case behavior.
Schema
sales(category TEXT, product TEXT, revenue REAL)
Examples
Example 1
Inputcategory A revenue is 100 total
Outputp1 share 0.3, p2 share 0.7
The window sum gives the category denominator on each product row.
Constraints
- Return only the requested columns.
- Use deterministic ORDER BY when multiple rows are returned.
- Assume SQLite-compatible SQL unless the prompt states otherwise.
CodeSQL
Visible browser tests run here when available.
Testcases1 visible / 3 hidden categories
Core SQL case
Inputcategory A revenue is 100 total
Expected[["A","p1",30,0.3],["A","p2",70,0.7],["B","q1",50,1]]
The window sum gives the category denominator on each product row.
Hidden Test Categories
Empty or missing matchesDuplicate rows or tiesNULL values where the pattern commonly breaks