Big Query filtering null rows of Custom query creating table

Question

I am trying to query my data in big query and want to avoid null records but keep getting them.

Here is my query so far:

select 
(SELECT x.value FROM UNNEST(user_properties) x 
WHERE x.key='restaurantName' 
and x.value is not null).string_value as restaurantName ,
(SELECT x.value FROM UNNEST(user_properties) x 
WHERE x.key='restaurantId' and x.value is not null).string_value as 
restaurantID , 
(SELECT x.value FROM UNNEST(user_properties) x 
WHERE x.key='user_id' and x.value is not null).string_value as user 
FROM some_data_set where event_name="ConfirmOrderBtn" and event_date between 
'20191110' and '_*' and app_info.id = "app_id"

Here are my query results:

Answer 1

Below is for BigQuery Standard SQL

#standardSQL
SELECT * FROM (
  SELECT 
    (SELECT x.value 
      FROM UNNEST(user_properties) x 
      WHERE x.key='restaurantName' 
      AND x.value IS NOT NULL
    ).string_value AS restaurantName ,
    (SELECT x.value 
      FROM UNNEST(user_properties) x 
      WHERE x.key='restaurantId' 
      AND x.value IS NOT NULL
    ).string_value AS restaurantID , 
    (SELECT x.value 
      FROM UNNEST(user_properties) x 
      WHERE x.key='user_id' 
      AND x.value IS NOT NULL
     ).string_value AS user 
  FROM `project.dataset.some_data_set` 
  WHERE event_name="ConfirmOrderBtn" 
  AND event_date BETWEEN '20191110' AND '_*' 
  AND app_info.id = "app_id" 
)
WHERE NOT (restaurantName IS NULL OR restaurantID IS NULL OR user IS NULL)