{
    "action": "final",
    "content": "**None of the columns have missing values.** The null-count query over all 18 analytical columns (user_id, age, gender, occupation_type, chronotype, bedtime_phone_minutes, primary_bedtime_app, screen_brightness_pct, blue_light_filter_active, caffeine_post_5pm_mg, physical_activity_min, sleep_latency_min, total_sleep_hours, deep_sleep_pct, rem_sleep_pct, morning_alarm_snoozes, next_day_fatigue_score, sleep_debt_category) returned a null count of 0 and 0.0% missing for every one of them, across the table's 8,500 rows.\n\nNotes:\n- The check covers only the 18 data columns. The four ingestion metadata columns (_ingestion_timestamp, _batch_id, _source_file, _source_system) were not part of this query.\n- This only detects true NULLs. Placeholder values such as empty strings, 0 or -1 used to mean \"unknown\" would not show up here. I did not check for them, so the data may still hold disguised missing values."
}