如何删除 BigQuery 中属于嵌套列的列

Question

我想删除 BigQuery table 中属于记录或嵌套列一部分的列。我在他们的 documentation 中找到了这个命令。遗憾的是，此命令不适用于现有 RECORD 字段内的嵌套列。有什么解决方法吗？

例如，如果我有这个架构，我想删除地址字段中的 address2 字段。所以从这个：

[
    {
        "name": "name",
        "type": "STRING",
        "mode": "NULLABLE"
    },
    {
        "name": "addresses",
        "type": "RECORD",
        "mode": "REPEATED",
        "fields": [
            {
                "name": "address1",
                "type": "STRING",
                "mode": "NULLABLE"
            },
            {
                "name": "address2",
                "type": "STRING",
                "mode": "NULLABLE"
            },
            {
                "name": "country",
                "type": "STRING",
                "mode": "NULLABLE"
            }
        ]
    }
]

对此：

[
    {
        "name": "name",
        "type": "STRING",
        "mode": "NULLABLE"
    },
    {
        "name": "addresses",
        "type": "RECORD",
        "mode": "REPEATED",
        "fields": [
            {
                "name": "address1",
                "type": "STRING",
                "mode": "NULLABLE"
            },
            {
                "name": "country",
                "type": "STRING",
                "mode": "NULLABLE"
            }
        ]
    }
]

Answer 1

下面使用

select * replace(
  array(select as struct * except(address2) from t.addresses) 
  as addresses)
from `project.dataset.table` t

如果您想永久删除该字段 - 使用 create or replace table 如下例

create or replace table `project.dataset.new_table` as 
select * replace(
  array(select as struct * except(address2) from t.addresses) 
  as addresses)
from `project.dataset.table` t

如何删除 BigQuery 中属于嵌套列的列

How to delete a column in BigQuery that is part of a nested column

nested-lists

google-bigquery

google-cloud-platform