Run a SQL query

Runs one read-only SELECT (DuckDB dialect) over the workspace's tables and returns a preview of the result. Table names come from locate's tables, read-file's sql_tables and the refusal of a query naming an unknown table, which lists them all. Every result is kept: result.handle (res_…) is a table the next query in this workspace may join, total or page with LIMIT/OFFSET, and result_citation.result_file is the whole result as a Parquet file, downloadable from its download_url without the API key until download_url_expires_at; it is not one of the workspace's files. A statement that isn't a read is refused. File reads and SQL queries together are limited to 600 per account every 10 minutes. Free.