如何将UNNEST函数转换为遗留sql

Question

我正在尝试了解旧版SQL。我有这个标准的SQL查询

SELECT event_param.value.String_value
FROM `bike_app.info_firebase_ANDROID.app_events_20170521`,
  UNNEST(event_dim) as event,
  UNNEST(event.params) as event_param,
  UNNEST(user_dim.user_properties) as user_prop
WHERE event.name = "add_mark"
  AND event_param.key = "item_id"
  AND user_prop.key = "age"
  AND (CAST(user_prop.value.value.string_value as FLOAT64)) > 10

完全符合我的要求。但我无法理解如何将此查询转换为遗留sql。请给我一些建议。