Feature Request: Support TABLESAMPLE

[nbiscaro]

Discussed in #429

^{Originally posted by dpxcc November 12, 2024}
The TABLESAMPLE clause is useful for sampling from large tables, but pg_duckdb doesn't support it right now due to syntax differences in TABLESAMPLE clause between Postgres and DuckDB: https://duckdb.org/docs/sql/samples.html

SET duckdb.force_execution = ON;
CREATE TABLE t (a int);
SELECT * FROM t TABLESAMPLE SYSTEM (10);

throws

WARNING:  (PGDuckDB/CreatePlan) Prepared query returned an error: 'Parser Error: Sample method System cannot be used with a discrete sample count, either switch to reservoir sampling or use a sample_size
 a 
---
(0 rows)

but it could be an error if we added some DuckDB-only function to the query