Allow usage of table functions in relations (#16571)

* Allow usage of table funstions in relations

* Rebase

Author: osipovartem

datafusion/sql/src/relation/mod.rs

@@ -154,6 +154,35 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
                     "UNNEST table factor with offset is not supported yet"
                 );
             }
+            TableFactor::Function {
+                name, args, alias, ..
+            } => {
+                let tbl_func_ref = self.object_name_to_table_reference(name)?;
+                let schema = planner_context
+                    .outer_query_schema()
+                    .cloned()
+                    .unwrap_or_else(DFSchema::empty);
+                let func_args = args
+                    .into_iter()
+                    .map(|arg| match arg {
+                        FunctionArg::Unnamed(FunctionArgExpr::Expr(expr))
+                        | FunctionArg::Named {
+                            arg: FunctionArgExpr::Expr(expr),
+                            ..
+                        } => {
+                            self.sql_expr_to_logical_expr(expr, &schema, planner_context)
+                        }
+                        _ => plan_err!("Unsupported function argument: {arg:?}"),
+                    })
+                    .collect::<Result<Vec<Expr>>>()?;
+                let provider = self
+                    .context_provider
+                    .get_table_function_source(tbl_func_ref.table(), func_args)?;
+                let plan =
+                    LogicalPlanBuilder::scan(tbl_func_ref.table(), provider, None)?
+                        .build()?;
+                (plan, alias)
+            }
             // @todo Support TableFactory::TableFunction?
             _ => {
                 return not_impl_err!(

datafusion/sqllogictest/test_files/table_functions.slt

@@ -482,3 +482,15 @@ SELECT * FROM range(DATE '2023-01-01', DATE '2023-01-02', INTERVAL '-1' DAY)
 
 query error DataFusion error: Error during planning: range function with dates requires exactly 3 arguments
 SELECT * FROM range(DATE '2023-01-01', DATE '2023-01-03')
+
+# Table function as relation
+statement ok
+CREATE OR REPLACE TABLE json_table (c INT) AS VALUES (1), (2);
+
+query II
+SELECT c, f.*  FROM json_table, LATERAL generate_series(1,2) f;
+----
+1 1
+1 2
+2 1
+2 2