當我嘗試取消嵌套數組字段時，BigQuery中出現“列名ID不明確”錯誤

Question

我有一個具有這樣的架構的BigQuery表（為簡潔起見，列出了重要的字段）：

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

我正在嘗試執行查詢，並獲得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

並得到一個錯誤： Column name id is ambiguous at [2:3]

如何在這里消除歧義？

Answer 1

您的第一個id是模棱兩可的。 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