Checkpoint: Querying with Intent

Question 1 of 5

• channel = ‘web’ AND coupon_code <> NULL AND order_date BETWEEN ‘2025-12-01’ AND ‘2025-12-31’
• channel = ‘web’ AND coupon_code IS NOT NULL AND order_date BETWEEN ‘2025-12-01’ AND ‘2025-12-31’
• channel = ‘web’ AND coupon_code IS NOT NULL AND order_date >= ‘2025-12-01’ AND order_date < ‘2026-01-01’
• channel = ‘web’ OR coupon_code IS NOT NULL AND order_date >= ‘2025-12-01’ AND order_date < ‘2026-01-01’

Question 2 of 5

• Tickets that are still open, because closed_at is NULL until a ticket is closed.
• Tickets that were closed on the same day they were opened.
• Duplicate tickets that COUNT(closed_at) removes.
• Tickets with no satisfaction score.

Question 3 of 5

CASE
  WHEN satisfaction >= 4 THEN 'happy'
  WHEN satisfaction <= 2 THEN 'unhappy'
END

• ‘happy’
• ‘unhappy’
• An error, because CASE can’t handle NULL inputs
• NULL, because no WHEN is TRUE and there’s no ELSE

Question 4 of 5

• In SQLite, ‘%w’ counts Monday as 0.
• strftime returns text, so the comparison should be with ‘0’, not the number 0.
• strftime can’t read the time part of opened_at.
• Weekday filters need julianday() instead.

Question 5 of 5

• ORDER BY order_date DESC LIMIT 25 OFFSET 25
• ORDER BY channel, order_date DESC LIMIT 25 OFFSET 25
• ORDER BY order_date DESC, order_id DESC LIMIT 25 OFFSET 25
• LIMIT 25 OFFSET 25 with no ORDER BY, since the table is already in date order