UPDATE product
SET p_ftime = CASE WHEN p_ftime is not NULL THEN p_ftime ELSE getDate() END,
p_state = 1
WHERE p_id = '1001'
SET p_ftime = CASE WHEN p_ftime is not NULL THEN p_ftime ELSE getDate() END,
p_state = 1
WHERE p_id = '1001'
SET p_ftime = IsNull(p_ftime,getdate()),
p_state = 1
WHERE p_id = '1001'
SET p_ftime =getDate(),
SET p_state = 1
WHERE p_id = '1001' and p_ftime is null
SET p_ftime=isnull(p_ftime,getDate()),
p_state = 1
WHERE p_id = '1001'