Ad Impression revenue sum

SELECT
  user_pseudo_id,
  event_name,
  EXTRACT(date FROM Parse_datetime('%Y%m%d', event_date)) AS event_date,
  (
    SELECT COALESCE(value.int_value, value.float_value, value.double_value, NULL)
    FROM UNNEST(event_params)
    WHERE
      KEY = 'value'
      AND event_name = 'ad_impression'
  ) AS ad_funded_revenue,
  (
    SELECT value.string_value
    FROM UNNEST(event_params)
    WHERE
      KEY = 'currency'
      AND event_name = 'ad_impression'
  ) AS ad_revenue_currency,
  (
    CASE
      WHEN event_name = 'in_app_purchase' THEN event_value_in_usd
      ELSE 0
      END) AS iap_revenue_usd,
FROM `bride-race-app-bundle.analytics_356190151.events_*`
WHERE
  platform = 'IOS'
  AND event_name IN (
    'in_app_purchase',
    'ad_impression')