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Related to PR #3309 which wants to add SQL support for tinyint and unsigned ints. The question is whether we want to support SQL access to underlying data types that Arrow supports.

Here's a table of integer data type support between Spark, Postgres, DataFusion, Arrow, and Parquet:

"SQL support" in this case means only 3 things, as far as I can tell:

• support for the data type in the CREATE EXTERNAL TABLE x (schema..) syntax
• support for the data type in the SQL CAST function
• no memory table support via CREATE TABLE x AS SELECT 1::tinyint unsigned syntax

Otherwise, the unsigned variants are already supported by DataFusion, because Arrow supports them. Unsigned integers can be in custom table providers, or in a parquet file.

Without SQL support for these data types, we won't be able to cast to unsigned types from SQL, nor load them from CSV/JSON.

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