I am trying to understand Legacy SQL. I have this standart sql query
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
which works perfectly as I want. But I can't catch how can I convert this query to legacy sql. Please, give me some advice.