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

I have a BigQuery table with schema like this (noly important fields are listed for brevity):

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

I'm trying to perform a query and get both id and products.id like this:

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

and get an error: Column name id is ambiguous at [2:3]

How do I remove ambiguity here?

Answer 1

Your first id is the ambiguous one. Just need to add the table source

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