Support CREATE TABLE x AS TABLE y (#704)

* first commit

* fix style and edit test

* fix test?

* remove unnecessary logic

* refactor implementation

* codestyle

* add schema support

* codestyle and lint

* Apply suggestions from code review

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

* PartialOrd and Ord

* clean up parser logic

* codestyle and lint

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

src/ast/mod.rs

@@ -33,7 +33,7 @@ pub use self::operator::{BinaryOperator, UnaryOperator};
 pub use self::query::{
     Cte, ExcludeSelectItem, Fetch, Join, JoinConstraint, JoinOperator, LateralView, LockType,
     Offset, OffsetRows, OrderByExpr, Query, Select, SelectInto, SelectItem, SetExpr, SetOperator,
-    SetQuantifier, TableAlias, TableFactor, TableWithJoins, Top, Values, With,
+    SetQuantifier, Table, TableAlias, TableFactor, TableWithJoins, Top, Values, With,
 };
 pub use self::value::{escape_quoted_string, DateTimeField, TrimWhereField, Value};
 

src/ast/query.rs

@@ -84,7 +84,7 @@ pub enum SetExpr {
     },
     Values(Values),
     Insert(Statement),
-    // TODO: ANSI SQL supports `TABLE` here.
+    Table(Box<Table>),
 }
 
 impl fmt::Display for SetExpr {
@@ -94,6 +94,7 @@ impl fmt::Display for SetExpr {
             SetExpr::Query(q) => write!(f, "({})", q),
             SetExpr::Values(v) => write!(f, "{}", v),
             SetExpr::Insert(v) => write!(f, "{}", v),
+            SetExpr::Table(t) => write!(f, "{}", t),
             SetExpr::SetOperation {
                 left,
                 right,
@@ -152,6 +153,31 @@ impl fmt::Display for SetQuantifier {
         }
     }
 }
+
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+/// A [`TABLE` command]( https://www.postgresql.org/docs/current/sql-select.html#SQL-TABLE)
+pub struct Table {
+    pub table_name: Option<String>,
+    pub schema_name: Option<String>,
+}
+
+impl fmt::Display for Table {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if let Some(ref schema_name) = self.schema_name {
+            write!(
+                f,
+                "TABLE {}.{}",
+                schema_name,
+                self.table_name.as_ref().unwrap(),
+            )?;
+        } else {
+            write!(f, "TABLE {}", self.table_name.as_ref().unwrap(),)?;
+        }
+        Ok(())
+    }
+}
+
 /// A restricted variant of `SELECT` (without CTEs/`ORDER BY`), which may
 /// appear either as the only body item of a `Query`, or as an operand
 /// to a set operation like `UNION`.

src/parser.rs

@@ -4368,6 +4368,14 @@ impl<'a> Parser<'a> {
             SetExpr::Query(Box::new(subquery))
         } else if self.parse_keyword(Keyword::VALUES) {
             SetExpr::Values(self.parse_values()?)
+        } else if self.parse_keyword(Keyword::TABLE) {
+            let token1 = self.peek_token();
+            let token2 = self.peek_nth_token(1);
+            let token3 = self.peek_nth_token(2);
+            self.next_token();
+            self.next_token();
+            self.next_token();
+            SetExpr::Table(Box::new(self.parse_as_table(token1, token2, token3)?))
         } else {
             return self.expected(
                 "SELECT, VALUES, or a subquery in the query body",
@@ -4566,6 +4574,52 @@ impl<'a> Parser<'a> {
         })
     }
 
+    /// Parse `CREATE TABLE x AS TABLE y`
+    pub fn parse_as_table(
+        &self,
+        token1: Token,
+        token2: Token,
+        token3: Token,
+    ) -> Result<Table, ParserError> {
+        let table_name;
+        let schema_name;
+        if token2 == Token::Period {
+            match token1 {
+                Token::Word(w) => {
+                    schema_name = w.value;
+                }
+                _ => {
+                    return self.expected("Schema name", token1);
+                }
+            }
+            match token3 {
+                Token::Word(w) => {
+                    table_name = w.value;
+                }
+                _ => {
+                    return self.expected("Table name", token3);
+                }
+            }
+            Ok(Table {
+                table_name: Some(table_name),
+                schema_name: Some(schema_name),
+            })
+        } else {
+            match token1 {
+                Token::Word(w) => {
+                    table_name = w.value;
+                }
+                _ => {
+                    return self.expected("Table name", token1);
+                }
+            }
+            Ok(Table {
+                table_name: Some(table_name),
+                schema_name: None,
+            })
+        }
+    }
+
     pub fn parse_set(&mut self) -> Result<Statement, ParserError> {
         let modifier =
             self.parse_one_of_keywords(&[Keyword::SESSION, Keyword::LOCAL, Keyword::HIVEVAR]);

tests/sqlparser_common.rs

@@ -2273,6 +2273,55 @@ fn parse_create_table_as() {
     }
 }
 
+#[test]
+fn parse_create_table_as_table() {
+    let sql1 = "CREATE TABLE new_table AS TABLE old_table";
+
+    let expected_query1 = Box::new(Query {
+        with: None,
+        body: Box::new(SetExpr::Table(Box::new(Table {
+            table_name: Some("old_table".to_string()),
+            schema_name: None,
+        }))),
+        order_by: vec![],
+        limit: None,
+        offset: None,
+        fetch: None,
+        lock: None,
+    });
+
+    match verified_stmt(sql1) {
+        Statement::CreateTable { query, name, .. } => {
+            assert_eq!(name, ObjectName(vec![Ident::new("new_table")]));
+            assert_eq!(query.unwrap(), expected_query1);
+        }
+        _ => unreachable!(),
+    }
+
+    let sql2 = "CREATE TABLE new_table AS TABLE schema_name.old_table";
+
+    let expected_query2 = Box::new(Query {
+        with: None,
+        body: Box::new(SetExpr::Table(Box::new(Table {
+            table_name: Some("old_table".to_string()),
+            schema_name: Some("schema_name".to_string()),
+        }))),
+        order_by: vec![],
+        limit: None,
+        offset: None,
+        fetch: None,
+        lock: None,
+    });
+
+    match verified_stmt(sql2) {
+        Statement::CreateTable { query, name, .. } => {
+            assert_eq!(name, ObjectName(vec![Ident::new("new_table")]));
+            assert_eq!(query.unwrap(), expected_query2);
+        }
+        _ => unreachable!(),
+    }
+}
+
 #[test]
 fn parse_create_table_on_cluster() {
     // Using single-quote literal to define current cluster