sqlparser-improvements.patch

diff --git a/src/ast/ddl.rs b/src/ast/ddl.rs
index 1234567..abcdefg 100644
--- a/src/ast/ddl.rs
+++ b/src/ast/ddl.rs
@@ -XXX,6 +XXX,50 @@ impl From<&'a str> for IndexColumn {
     }
 }
 
+impl IndexColumn {
+    /// 提取简单的列名
+    /// 
+    /// 对于简单的列引用（如 `column_name`），返回列名
+    /// 对于复合标识符（如 `table.column`），返回最后一部分
+    /// 对于复杂表达式（如函数索引），返回 None
+    /// 
+    /// # Examples
+    /// 
+    /// ```
+    /// use sqlparser::ast::*;
+    /// use sqlparser::dialect::MySqlDialect;
+    /// use sqlparser::parser::Parser;
+    /// 
+    /// let dialect = MySqlDialect {};
+    /// let sql = "CREATE INDEX idx ON users (username)";
+    /// let ast = Parser::parse_sql(&dialect, sql).unwrap();
+    /// 
+    /// if let Statement::CreateIndex(create_index) = &ast[0] {
+    ///     let col = &create_index.columns[0];
+    ///     assert_eq!(col.simple_column_name(), Some("username"));
+    /// }
+    /// ```
+    pub fn simple_column_name(&self) -> Option<&str> {
+        match &self.column.expr {
+            crate::ast::Expr::Identifier(ident) => Some(&ident.value),
+            crate::ast::Expr::CompoundIdentifier(idents) => {
+                idents.last().map(|id| id.value.as_str())
+            }
+            _ => None,
+        }
+    }
+
+    /// 获取列名（包括复杂表达式）
+    /// 
+    /// 对于简单列返回列名，对于复杂表达式返回其字符串表示
+    pub fn column_name(&self) -> String {
+        self.simple_column_name()
+            .map(|s| s.to_string())
+            .unwrap_or_else(|| self.column.to_string())
+    }
+}
+
 impl fmt::Display for IndexColumn {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}", self.column)?;
@@ -YYY,6 +YYY,60 @@ impl fmt::Display for CreateIndex {
     }
 }
 
+impl CreateIndex {
+    /// 提取所有简单列名
+    /// 
+    /// 只返回简单的列引用，忽略复杂表达式（如函数索引）
+    /// 
+    /// # Examples
+    /// 
+    /// ```
+    /// use sqlparser::ast::*;
+    /// use sqlparser::dialect::MySqlDialect;
+    /// use sqlparser::parser::Parser;
+    /// 
+    /// let dialect = MySqlDialect {};
+    /// let sql = "CREATE INDEX idx ON posts (user_id, created_at)";
+    /// let ast = Parser::parse_sql(&dialect, sql).unwrap();
+    /// 
+    /// if let Statement::CreateIndex(create_index) = &ast[0] {
+    ///     let names = create_index.simple_column_names();
+    ///     assert_eq!(names, vec!["user_id", "created_at"]);
+    /// }
+    /// ```
+    pub fn simple_column_names(&self) -> Vec<&str> {
+        self.columns
+            .iter()
+            .filter_map(|col| col.simple_column_name())
+            .collect()
+    }
+
+    /// 提取所有列名（包括复杂表达式）
+    /// 
+    /// 对于简单列返回列名，对于复杂表达式返回其字符串表示
+    pub fn column_names(&self) -> Vec<String> {
+        self.columns
+            .iter()
+            .map(|col| col.column_name())
+            .collect()
+    }
+
+    /// 获取索引名称（如果有）
+    pub fn index_name(&self) -> Option<String> {
+        self.name.as_ref().map(|n| n.to_string())
+    }
+
+    /// 获取表名
+    pub fn table_name_str(&self) -> String {
+        self.table_name.to_string()
+    }
+
+    /// 检查是否是唯一索引
+    pub fn is_unique(&self) -> bool {
+        self.unique
+    }
+}
+
 /// ALTER TABLE operation REPLICA IDENTITY values
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]