select *
from (
select country_region, date, confirmed, deaths
,LAG(confirmed, 1) OVER (PARTITION BY country_region ORDER BY date ASC) AS prev_day
,confirmed - LAG(confirmed, 1) OVER (PARTITION BY country_region ORDER BY date ASC) as new_cases
from `bigquery-public-data.covid19_jhu_csse.summary`
WHERE upper(country_region) = 'HUNGARY' AND
date between '2021-09-21' AND (select max(date) from
`bigquery-public-data.covid19_jhu_csse.summary`)
)
WHERE new_cases > 0
ORDER BY 2 asc