Convert Timestamps for Database Queries

MySQL, PostgreSQL, and SQLite store UNIX_TIMESTAMP() values as seconds since the epoch. Use "Date → Timestamp" to build accurate WHERE clauses.

MongoDB stores dates as milliseconds. Use millisecond mode when filtering by ISODate in aggregation pipelines.

Avoid timezone surprises: always convert to UTC timestamp for database storage, then convert back to local time only in the display layer.

Copy the seconds timestamp directly into your SQL query: WHERE created_at BETWEEN 1700000000 AND 1700086400.