使用子查询和 INNER JOIN 时出现问题别名表

Question

我正在尝试打印来自不同站点的 ID 和名称以及该站点的总乘车次数。

ID 和姓名来自

stations

表，而旅行次数来自

trips

表，所以我创建了一个如下形式的查询：

SELECT id, name and num_rides
FROM (SELECT COUNT (*) num_rides
    FROM tableB AS b) AS num_rides
INNER JOIN tableA AS a ON  a.station_id = b.start_station_id

问题是外部查询的 JOIN 语句无法识别我的表的

b

别名，我在内部查询中为其添加了别名。

我尝试单独运行查询，它们都工作正常。

为什么计算机不记得我在外部查询中的内部查询别名？

错误：

Unrecognized name: trips

，trips 是我用于表 B 的别名。

SELECT 
    station_id,
    name,
    num_of_rides AS num_of_rides_starting_at
FROM
    (
        SELECT
            start_station_id,
            COUNT(*) number_of_rides
        FROM
            bigquery-public-data.new_york_citibike.citibike_trips AS trips
        GROUP BY
            trips.start_station_id
    )
    AS num_of_rides
INNER JOIN
    bigquery-public-data.new_york_citibike.citibike_stations AS stations
ON stations.station_id = trips.start_station_id
ORDER BY num_of_rides DESC

Answer 1

我认为问题在于“旅行”别名仅在括号内有效。尝试命名整个 select 语句并引用该名称。

SELECT 
   station_id,
   name,
   num_of_rides AS num_of_rides_starting_at
FROM
   (
       SELECT
           start_station_id,
           COUNT(*) number_of_rides
       FROM
           bigquery-public-data.new_york_citibike.citibike_trips AS trips
       GROUP BY
           trips.start_station_id
   ) NeedNameHere
   AS num_of_rides
INNER JOIN
bigquery-public-data.new_york_citibike.citibike_stations AS stations 
   ON stations.station_id = NeedNameHere.start_station_id
ORDER BY num_of_rides DESC 

Answer 2

SELECT 
    station_id, /*from table: citibike_stations */
    name, /*from table: citibike_trips */
    number_of_rides AS number_of_rides_starting_at_station /*from table: station_num_trips*/
FROM
   (SELECT  
        start_station_id,
        COUNT(*) number_of_rides
    FROM `bigquery-public-data.new_york_citibike.citibike_trips` 
    GROUP BY start_station_id
   )
   AS station_num_trips
INNER JOIN `bigquery-public-data.new_york_citibike.citibike_stations` 
ON station_id = start_station_id
ORDER BY number_of_rides DESC