BigQuery:如何将其中一列的类型从 INTEGER 更改为 STRING? [英] BigQuery: How can I change the type of one of my column from INTEGER to STRING?

问题描述

在 BigQuery 中，假设我有一个包含 X 字段的现有表.字段 1 当前是整数，但我想将其更改为字符串.

我需要保留当前在字段 1 中的数据，同时能够将字符串数据插入到该字段中.

我认为目前在 Google BigQuery 中无法修改列的类型.我认为我们可以对表进行的唯一修改是添加带有 Table.Update 命令

那么最好的方法是什么?

我正在考虑这样做，但我希望有更好的解决方案:

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1. 从 MyTable 中选择 STRING(field1) 作为 field1、field2、field3、fieldX
2. 将结果导出到 TempTable
3. 删除我的表
4. 将 TempTable 复制到 MyTable

然后我就可以在 field1 中插入字符串了.

解决方案

步骤 1-4 都可以在一个原子步骤中完成.只需在您的查询上设置一个目标表并使用 allow_large_results 并使用 write_truncate 将您的结果写回原始表.这将更新您的表格.

In BigQuery, let say I have an existing table with X fields. Field 1 is currently an INTEGER but I would like to change it to a STRING.

I need to keep data that is currently in Field 1, while being able to insert string data into that field.

I believe that it is currently impossible in Google BigQuery to modify the type of a column. I think that the only modification that we can do to a table is add columns with the Table.Update command

So what would be the best way do to that?

I was thinking of doing this, but I would hope that there is a better solution:

1. Select STRING(field1) as field1, field2, field3, fieldX from MyTable
2. Export the result in a TempTable
3. Delete MyTable
4. Copy TempTable to MyTable

I would then be able to insert strings in field1.

解决方案

Steps 1-4 can all be done in a single atomic step. Just set a destination table on your query and use allow_large_results and use write_truncate to write your results back to the original table. This will update your table in place.

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