BigQuery 中的多个左连接

Question

我正在尝试使我在 BigQuery 中的当前正在运行的 SQL 查询更加精简，但遇到了以下问题：

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错误：ON 子句必须是 AND of = 比较每个表中的一个字段名称，所有字段名称都以表名称为前缀。考虑使用标准 SQL .google.com/bigquery/docs/reference/standard-sql/)，它允许不等式 JOIN 以及涉及表达式和残差谓词的比较。

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下面是给出上述错误的查询。第一个 LEFT JOIN 有效。当我在下面添加第二个时，我开始收到错误。我要做的是获取人类可读的 own.o.firstname 和 own.o.lastname 值，而不是交易记录的 owner_id 值（o.properties.hubspot_owner_id.value），但为了做到这一点，我需要加入一些表。

我不得不在第二个 JOIN 的 ON 子句上使用 CAST，因为每个表的各自架构中的字段类型不同。如果我不这样做，我会收到以下错误：错误：连接键 o.properties.hubspot_owner_id.value (string) 和 o.ownerid (int64) 的类型无法自动强制。

WHERE 子句只是一个禁止列表，不返回已从数据库中删除的条目。

SELECT o.*
FROM (
  SELECT
    o.dealid,
    o.properties.dealname.value,
    stages.Label,
    o.properties.closedate.value,
    o.properties.hubspot_owner_id.value,
    own.o.firstname,
    own.o.lastname,
    o.properties.amount.value,
    o.properties.createdate.value,
    o.properties.pipeline.value,
    o.associations.associatedcompanyids,
    ROW_NUMBER() OVER (PARTITION BY o.dealid ORDER BY o._sdc_batched_at DESC) as seqnum
  FROM [sample-table:hubspot.deals] o
  LEFT JOIN [sample-table:hubspot.sales_stages_lookup] stages ON o.properties.dealstage.value = stages.Internal_Value
  LEFT JOIN [sample-table:hubspot.owners_reporting] own ON CAST(o.properties.hubspot_owner_id.value AS INTEGER) = CAST(own.o.ownerid AS INTEGER)) o
WHERE o.dealid NOT IN (SELECT objectid FROM [sample-table:hubspot_suppression_list.data] WHERE subscriptiontype = 'deal.deletion') AND seqnum = 1

Answer 1

在 BigQuery 中改用 standard SQL，它支持将表达式作为 ON 子句的一部分：

#standardSQL
SELECT o.*
FROM (
  SELECT
    o.dealid,
    o.properties.dealname.value AS dealname_value,
    stages.Label,
    o.properties.closedate.value AS closedate_value,
    o.properties.hubspot_owner_id.value AS hubspot_owner_id_value,
    own.o.firstname,
    own.o.lastname,
    o.properties.amount.value AS amount_value,
    o.properties.createdate.value AS createdate_value,
    o.properties.pipeline.value AS pipeline_value,
    o.associations.associatedcompanyids,
    ROW_NUMBER() OVER (PARTITION BY o.dealid ORDER BY o._sdc_batched_at DESC) as seqnum
  FROM `sample-table.hubspot.deals` o
  LEFT JOIN `sample-table.hubspot.sales_stages_lookup` stages ON o.properties.dealstage.value = stages.Internal_Value
  LEFT JOIN `sample-table.hubspot.owners_reporting` own ON CAST(o.properties.hubspot_owner_id.value AS INT64) = CAST(own.o.ownerid AS INT64)) o
WHERE o.dealid NOT IN (SELECT objectid FROM `sample-table.hubspot_suppression_list.data` WHERE subscriptiontype = 'deal.deletion') AND seqnum = 1

如需详细了解 BigQuery 中旧版 SQL 和标准 SQL 之间的区别，请参阅migration guide。