Public SQL challenges shared by the EraCode community. These pages are teasers — skill maintenance starts when you attempt the full problem inside EraCode.
Practice treating a SQL transaction as the “request scope” so multiple queries in one request see a consistent view of data.
Practice a common SQL idiom for picking the latest record per group using a window function, plus a quick concept check about trade-offs.
Practice using SQL module-like organization via schemas by calling a function from a different schema safely and explicitly.