-- Sequential progressive dates - no going backwards
UPDATE scheduled_message_batches smb
JOIN (
    SELECT 
        id,
        scheduled_message_id,
        batch_number,
        ROW_NUMBER() OVER (PARTITION BY scheduled_message_id ORDER BY batch_number) as seq_num
    FROM scheduled_message_batches
) ranked ON smb.id = ranked.id
SET smb.scheduled_for = CONCAT(
    '2025-12-',
    LPAD(10 + ranked.seq_num, 2, '0'),  -- Sequential: 11, 12, 13, 14, 15, 16
    ' ',
    LPAD(9 + FLOOR(RAND() * 9), 2, '0'),
    ':',
    CASE WHEN RAND() > 0.5 THEN '30' ELSE '00' END,
    ':00'
);