create table: add clone syntax (#542)

Signed-off-by: Maciej Obuchowski <obuchowski.maciej@gmail.com>

tests/sqlparser_common.rs

@@ -1992,6 +1992,18 @@ fn parse_create_table_with_options() {
     }
 }
 
+#[test]
+fn parse_create_table_clone() {
+    let sql = "CREATE OR REPLACE TABLE a CLONE a_tmp";
+    match verified_stmt(sql) {
+        Statement::CreateTable { name, clone, .. } => {
+            assert_eq!(ObjectName(vec![Ident::new("a")]), name);
+            assert_eq!(Some(ObjectName(vec![(Ident::new("a_tmp"))])), clone)
+        }
+        _ => unreachable!(),
+    }
+}
+
 #[test]
 fn parse_create_table_trailing_comma() {
     let sql = "CREATE TABLE foo (bar int,)";