Pranav, This is a good question. To me, I would take this as a bug, and we could improve the RelToSqlConverter to treat BindableTableScan specially. Could you please help log a Jira issue? Contributions are welcome!
Pranav Deshpande <[email protected]> 于2022年8月20日周六 02:13写道： > Hi Team, > How can I convert a BindableTableScan with projects and Filters back to a > RelTree with a project node, a filter node and a tablescan node? > > I am doing this because I encountered the following issue (steps detailed > below). > > 1. I have a query:eg. Select colA, colB from myTable where colA > 1; > 2. The logical plan for this is a filter on top of a project on top of a > TableScan. > 3. If the table we created is a ProjectableFilterableTable and we have > added the ProjectTableScan rule etc., then after optimization we have a > single node which is a tablescan that contains filters and project and can > be executed by the bindable convention. > 4. If I convert this node to a SQL, I get the wrong SQL. > > To get a SQL, I do the following: > > RelToSqlConverter converter = new > RelToSqlConverter(SqlDialect.DatabaseProduct.CALCITE.getDialect()); > SqlNode sqlNode = converter.visitRoot(rablescan).asStatement(); > > This only gives me Select * from myTable; > > However, if I only have a ScannableTable and we haven't added the > ProjectTableScan rule etc. then for the physical plan we also get a > BindableFilter on top of a BindableProject on top of a BindableTablescan. > > If i convert this back using the same code then I get the correct statement > back: Select colA, colB from myTable where colA > 1 > > Hence I would like to know how to convert a BindableTableScan with projects > and Filters back to a RelTree with a project node, a filter node and a > tablescan node & would appreciate the community's help on the same. > > Thanks & Regards, > Pranav > -- Best, Benchao Li
