Track · 3:03 · Liner note
The Silent JOIN
A silent join is one that returns wrong results without any error, for example an inner join that drops unmatched rows or a many-to-many join that multiplies them.
The query ran, the numbers look reasonable and revenue is exactly twice what finance expects. The Silent JOIN does not crash; it fans out rows through a many-to-many relationship, or drops them through an inner join, and lets you publish the result.
Defend yourself with cheap checks: compare row counts before and after each join, assert uniqueness on the key you expect to be unique and test totals against an independent source. Fluent SQL makes it easy to write a plausible query. Habits are what make it a correct one.