问题
I have to push parquet file data which I am reading from IBM Cloud SQL Query to Db2 on Cloud.
My parquet file has data in array format, and I want to push that to DB2 on Cloud too.
Is there any way to push that array data of parquet file to Db2 on Cloud?
回答1:
Have you checked out this advise in the documentation?
https://cloud.ibm.com/docs/services/sql-query?topic=sql-query-overview#limitations
If a JSON, ORC, or Parquet object contains a nested or arrayed structure, a query with CSV output using a wildcard (for example, SELECT * from cos://...) returns an error such as "Invalid CSV data type used: struct." Use one of the following workarounds:
- For a nested structure, use the FLATTEN table transformation function.
- Alternatively, you can specify the fully nested column names instead of the wildcard, for example,
SELECT address.city, address.street, ... from cos://....- For an array, use the Spark SQL explode() function, for example,
select explode(contact_names) from cos://....
来源：https://stackoverflow.com/questions/60881918/how-to-flatten-an-parquet-array-datatype-when-using-ibm-cloud-sql-query