BigQuery - 使用子查询和 OR 语句连接多个条件 [英] BigQuery - Joining on multiple conditions using subqueries and OR statements

问题描述

无论如何要在多个潜在条件下连接两个表吗?

Is there anyway to join two tables on multiple potential conditions?

我目前正在将一些代码从 Postgres 迁移到 Bigquery，在那里我加入了多个潜在值，例如:

I'm currently migrating some code from Postgres to Bigquery where I joined on multiple potential values like:

SELECT
 *
FROM
 (
 SELECT
   offer_table.offer_id
   ,customer_table.customer_name
   ,customer_table.visit_count
   ,ROW_NUMBER() OVER (PARTITION BY offer_table.offer_id ORDER BY customer_table.visit_count DESC) AS customer_visit_rank
 FROM
   offer_table
   LEFT JOIN customer_table ON
    (
    offer_table.customer_id = customer_table.customer_id
    OR offer_table.email = customer_table.email
    OR offer_table.phone = customer_table.phone
    )
 ) dummy
WHERE
  customer_visit_rank = 1

我需要这样做是因为我的报价和客户数据在我们的 ID、电子邮件和电话字段的使用不一致，但都是有效的潜在匹配项.如果多个字段都有效(例如:id 和 email 匹配)，则会出现重复的行，我会在使用 ORDER BY 部分进行排名后根据 row_number 列将它们过滤掉.

I needed to this because my offer and customer data had inconsistent usage of our id, email, and phone fields but all were valid potential matches. If multiple fields worked (ex: id and email matched), there would be duplicate rows and I'd filter them out based on the row_number column after ranking using the ORDER BY section.

但是，当我尝试在 BigQuery 中加入多个条件时，我收到此错误消息:

However when I try to join on multiple conditions in BigQuery, I get this error message:

LEFT OUTER JOIN 不能在没有条件是连接两侧的字段相等的情况下使用.

有没有人想出一个解决方案来连接多个值而不是执行上述操作?

Has anyone figured out a solution to join on multiple values instead of doing the above?

推荐答案

你可以写单独的查询，然后使用COALESCE:

You can write separate queries, then use COALESCE:

SELECT
  *
FROM
  (
    SELECT
      offer_table.offer_id
      ,COALESCE(c1.customer_name,c2.customer_name,c3.customer_name)
      ,COALESCE(c1.visit_count,c2.visit_count,c3.visit_count)
      ,ROW_NUMBER() OVER (PARTITION BY offer_table.offer_id ORDER BY customer_table.visit_count DESC) AS customer_visit_rank
    FROM
      offer_table
    LEFT JOIN customer_table c1
      ON offer_table.customer_id = customer_table.customer_id
    LEFT JOIN customer_table c2
      ON offer_table.email = customer_table.email
    LEFT JOIN customer_table c3
      ON offer_table.phone = customer_table.phone
   )
 ) AS dummy
WHERE
  customer_visit_rank = 1

这篇关于BigQuery - 使用子查询和 OR 语句连接多个条件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！