When I use https://developers.google.com/bigquery/docs/reference/v2/tables/insert#try-it to upload a JSON file with not all fields inserted in all columns, it is accepted and I get nulls in my data.
When I use bq load and have a schema with mode nullable on possibly missing columns, the same file is rejected because there are different numbers of columns than in the schema.
If I add those columns to the JSON and set them to have a value null, I get an error because bq can't convert that to a string.
If I add those columns to the JSON and set them to have a value '' then the upload proceeds just fine..but now I have empty strings rather than null. Which is not what I want.
How can I tell the bq tool to let me upload nulls as nulls into a nullable column?
