Why Alibaba Bans Joins Over Three Tables – A Must‑Know Rule for SQL Engineers
Alibaba’s Java Development Manual mandates that any SQL involving more than three tables must be avoided, a rule that stems from the exponential cost of multi‑table joins in a single‑instance database, prompting engineers to rethink data modeling, adopt denormalization, wide tables, materialized views, CQRS or application‑level assembly instead of relying on complex joins.
