Clickhouse: support empty parenthesized options (apache#1925)

Author: solontsev

src/parser/mod.rs

@@ -16285,9 +16285,9 @@ impl<'a> Parser<'a> {
 
     fn parse_parenthesized_identifiers(&mut self) -> Result<Vec<Ident>, ParserError> {
         self.expect_token(&Token::LParen)?;
-        let partitions = self.parse_comma_separated(|p| p.parse_identifier())?;
+        let idents = self.parse_comma_separated0(|p| p.parse_identifier(), Token::RParen)?;
         self.expect_token(&Token::RParen)?;
-        Ok(partitions)
+        Ok(idents)
     }
 
     fn parse_column_position(&mut self) -> Result<Option<MySQLColumnPosition>, ParserError> {

tests/sqlparser_clickhouse.rs

@@ -224,6 +224,10 @@ fn parse_create_table() {
     clickhouse().verified_stmt(
         r#"CREATE TABLE "x" ("a" "int") ENGINE = MergeTree ORDER BY "x" AS SELECT * FROM "t" WHERE true"#,
     );
+    clickhouse().one_statement_parses_to(
+        "CREATE TABLE x (a int) ENGINE = MergeTree() ORDER BY a",
+        "CREATE TABLE x (a INT) ENGINE = MergeTree ORDER BY a",
+    );
 }
 
 #[test]