Make Table's ColumnDefs optional

Author: aharpervc

src/ast/data_type.rs

@@ -49,7 +49,7 @@ pub enum DataType {
     ///
     /// [PostgreSQL]: https://www.postgresql.org/docs/15/sql-createfunction.html
     /// [MsSQL]: https://learn.microsoft.com/en-us/sql/t-sql/statements/create-function-transact-sql?view=sql-server-ver16#c-create-a-multi-statement-table-valued-function
-    Table(Vec<ColumnDef>),
+    Table(Option<Vec<ColumnDef>>),
     /// Table type with a name, e.g. CREATE FUNCTION RETURNS @result TABLE(...).
     NamedTable(
         /// Table name.
@@ -724,12 +724,14 @@ impl fmt::Display for DataType {
             DataType::Unspecified => Ok(()),
             DataType::Trigger => write!(f, "TRIGGER"),
             DataType::AnyType => write!(f, "ANY TYPE"),
-            DataType::Table(fields) => {
-                if fields.is_empty() {
-                    return write!(f, "TABLE");
+            DataType::Table(fields) => match fields {
+                Some(fields) => {
+                    write!(f, "TABLE({})", display_comma_separated(fields))
                 }
-                write!(f, "TABLE({})", display_comma_separated(fields))
-            }
+                None => {
+                    write!(f, "TABLE")
+                }
+            },
             DataType::NamedTable(name, fields) => {
                 write!(f, "{} TABLE ({})", name, display_comma_separated(fields))
             }

src/parser/mod.rs

@@ -5221,9 +5221,19 @@ impl<'a> Parser<'a> {
                     p.peek_token().span.start
                 )?
             };
+
+            if table_column_defs.is_none()
+                || table_column_defs.clone().is_some_and(|tcd| tcd.is_empty())
+            {
+                parser_err!(
+                    "Expected table column definitions after TABLE keyword",
+                    p.peek_token().span.start
+                )?
+            }
+
             Ok(DataType::NamedTable(
                 ObjectName(vec![ObjectNamePart::Identifier(return_table_name)]),
-                table_column_defs.clone(),
+                table_column_defs.clone().unwrap(),
             ))
         })?;
 
@@ -9835,10 +9845,10 @@ impl<'a> Parser<'a> {
                 }
                 Keyword::TABLE => {
                     if self.peek_token() != Token::LParen {
-                        Ok(DataType::Table(Vec::<ColumnDef>::new()))
+                        Ok(DataType::Table(None))
                     } else {
                         let columns = self.parse_returns_table_columns()?;
-                        Ok(DataType::Table(columns))
+                        Ok(DataType::Table(Some(columns)))
                     }
                 }
                 Keyword::SIGNED => {