fix: create index using function

src/ast/mod.rs

@@ -1157,6 +1157,7 @@ pub enum Statement {
         /// index name
         name: ObjectName,
         table_name: ObjectName,
+        using: Option<Ident>,
         columns: Vec<OrderByExpr>,
         unique: bool,
         if_not_exists: bool,
@@ -2075,18 +2076,24 @@ impl fmt::Display for Statement {
             Statement::CreateIndex {
                 name,
                 table_name,
+                using,
                 columns,
                 unique,
                 if_not_exists,
-            } => write!(
-                f,
-                "CREATE {unique}INDEX {if_not_exists}{name} ON {table_name}({columns})",
-                unique = if *unique { "UNIQUE " } else { "" },
-                if_not_exists = if *if_not_exists { "IF NOT EXISTS " } else { "" },
-                name = name,
-                table_name = table_name,
-                columns = display_separated(columns, ",")
-            ),
+            } => {
+                write!(
+                    f,
+                    "CREATE {unique}INDEX {if_not_exists}{name} ON {table_name}",
+                    unique = if *unique { "UNIQUE " } else { "" },
+                    if_not_exists = if *if_not_exists { "IF NOT EXISTS " } else { "" },
+                    name = name,
+                    table_name = table_name
+                )?;
+                if let Some(value) = using {
+                    write!(f, " USING {} ", value)?;
+                }
+                write!(f, "({})", display_separated(columns, ","))
+            },
             Statement::CreateRole {
                 names,
                 if_not_exists,

src/parser.rs

@@ -2695,12 +2695,18 @@ impl<'a> Parser<'a> {
         let index_name = self.parse_object_name()?;
         self.expect_keyword(Keyword::ON)?;
         let table_name = self.parse_object_name()?;
+        let using = if self.expect_keyword(Keyword::USING).is_ok() {
+            Some(self.parse_identifier()?)
+        }else {
+            None
+        };
         self.expect_token(&Token::LParen)?;
         let columns = self.parse_comma_separated(Parser::parse_order_by_expr)?;
         self.expect_token(&Token::RParen)?;
         Ok(Statement::CreateIndex {
             name: index_name,
             table_name,
+            using,
             columns,
             unique,
             if_not_exists,

tests/sqlparser_common.rs

@@ -5052,9 +5052,45 @@ fn parse_create_index() {
             columns,
             unique,
             if_not_exists,
+            ..
+        } => {
+            assert_eq!("idx_name", name.to_string());
+            assert_eq!("test", table_name.to_string());
+            assert_eq!(indexed_columns, columns);
+            assert!(unique);
+            assert!(if_not_exists)
+        }
+        _ => unreachable!(),
+    }
+}
+
+#[test]
+fn test_create_index_with_using_function() {
+    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test USING btree (name,age DESC)";
+    let indexed_columns = vec![
+        OrderByExpr {
+            expr: Expr::Identifier(Ident::new("name")),
+            asc: None,
+            nulls_first: None,
+        },
+        OrderByExpr {
+            expr: Expr::Identifier(Ident::new("age")),
+            asc: Some(false),
+            nulls_first: None,
+        },
+    ];
+    match verified_stmt(sql) {
+        Statement::CreateIndex {
+            name,
+            table_name,
+            using,
+            columns,
+            unique,
+            if_not_exists,
         } => {
             assert_eq!("idx_name", name.to_string());
             assert_eq!("test", table_name.to_string());
+            assert_eq!("btree", using.unwrap().to_string());
             assert_eq!(indexed_columns, columns);
             assert!(unique);
             assert!(if_not_exists)
@@ -5063,6 +5099,7 @@ fn parse_create_index() {
     }
 }
 
+
 #[test]
 fn parse_drop_index() {
     let sql = "DROP INDEX idx_a";