Routine~11min

The Out-of-Range Rating

Product star averages look off. Seven reviews submitted via the mobile app have rating=0 — a bug sent 0 instead of 1 when users tapped the first star too quickly. Seven more have rating=6 from an old API version that allowed a 6-star option. Both sets are skewing averages on product pages. Three NULL-rating drafts are unrelated.

Tables you'll query

productsreviews

What you'll learn

SELECT & FilteringAggregations & GROUP BY
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