mysql - 在 pentaho 数据集成 (cdb) 上查询 mysql 时出错

Question

mysql查询是:

SELECT
    dim_location.country_name,
    COUNT(fact_flight.sk_fact)
FROM
    dim_location, dim_date
    INNER JOIN fact_flight ON dim_location.sk_location = fact_flight.sk_location
WHERE
    fact_flight.date_key = dim_date.date_key
GROUP BY
    dim_location.country_name

但它不起作用，这是错误消息

#1054 - Unknown column 'dim_location.sk_location' in 'on clause'

Answer 1

请按照下面给出的查询对 FROM 子句中的表重新排序；否则，用于连接 dim_location 和 fact_flight 表的 ON 子句中的连接条件将错误地应用于 dim_date 和 fact_flight 表会导致上述错误:

SELECT
    dim_location.country_name,
    COUNT(fact_flight.sk_fact)
FROM
    dim_date, dim_location
    INNER JOIN fact_flight ON dim_location.sk_location = fact_flight.sk_location
WHERE
    fact_flight.date_key = dim_date.date_key
GROUP BY
    dim_location.country_name