当我尝试取消嵌套数组字段时，BigQuery中出现“列名ID不明确”错误

Question

我有一个具有这样的架构的BigQuery表（为简洁起见，列出了重要的字段）：

id [STRING]
products [RECORD]
products.id [STRING]

我正在尝试执行查询，并获得id和products.id，如下所示：

SELECT 
  id as transaction_id,
  products.id as product_id
FROM 
  `my-project.set.transactions_table`,
  UNNEST(products) as products

并得到一个错误： Column name id is ambiguous at [2:3]

如何在这里消除歧义？

Answer 1

您的第一个id是模棱两可的。 只需要添加表源

SELECT 
  transactions.id as transaction_id,
  products.id as product_id
FROM 
  `my-project.set.transactions_table` as transactions,
  UNNEST(products) as products