引用my previous answer:
SELECT date('now', 'start of month') AS Date
UNION ALL
SELECT date('now', 'start of month', '+1 days')
UNION ALL
SELECT date('now', 'start of month', '+2 days')
UNION ALL
...
UNION ALL
SELECT date('now', 'start of month', '+27 days')
UNION ALL
SELECT date('now', 'start of month', '+28 days') WHERE strftime('%m', 'now', 'start of month', '+28 days') = strftime('%m', 'now')
UNION ALL
SELECT date('now', 'start of month', '+29 days') WHERE strftime('%m', 'now', 'start of month', '+29 days') = strftime('%m', 'now')
UNION ALL
SELECT date('now', 'start of month', '+30 days') WHERE strftime('%m', 'now', 'start of month', '+30 days') = strftime('%m', 'now')