[ ] 支持如下case: select Prompt('which year is the latest year we can get') as year, Prompt('the number of paper') as num From File('a.txt', 'text'), File('nips2024.txt'), File('nips2023.txt', 'text') Left Join tb_cooperating_author Where Prompt('research area is AI + Database');
desc
、查询元数据等方式,获取表的schemasome use case need to be fixed:
1
select t1.a from t1; +------+------+ | t1.a | t1.b | +------+------+ | 1 | None | | 2 | None | +------+------+
2
andb> >? explain select a from t1 group by t1.a; +---------------------------------------+------------------------------------------------------------------------+ | logical plan | physical plan | +---------------------------------------+------------------------------------------------------------------------+ | -> Query | -> Query | | | startup_cost: 0, total_cost: 0 | | -> Scan | -> TableScan | | table_name: t1, condition: None | table_name: t1, table_oid: 10000, startup_cost: 0, total_cost: 0 | +---------------------------------------+------------------------------------------------------------------------+ Effect Rows: 0
3 扫描结果物化 TableScan
andb> >? explain select * from t1, t1; +---------------------------------------------------+--------------------------------------------------------------------------------------+ | logical plan | physical plan | +---------------------------------------------------+--------------------------------------------------------------------------------------+ | -> Query | -> Query | | | startup_cost: 0, total_cost: 0 | | -> Join | -> NestedLoopJoin | | join_condition: None, join_type: CROSS JOIN | join_type: CROSS JOIN, condition: Filter: None, startup_cost: 0, total_cost: 0 | | -> Scan | -> TableScan | | table_name: t1, condition: None | table_name: t1, table_oid: 10000, startup_cost: 0, total_cost: 0 | | -> Scan | -> TableScan | | table_name: t1, condition: None | table_name: t1, table_oid: 10000, startup_cost: 0, total_cost: 0 | +---------------------------------------------------+--------------------------------------------------------------------------------------+
似乎Scan没有投影,全都扫描上来了?
4 无法扫描系统表
select * from andb_class;