Add SQLOrderBy struct to replace ASTNode::OrderByExpr

src/sqlast.rs

@@ -72,7 +72,7 @@ pub enum ASTNode {
         /// WHERE
         selection: Option<Box<ASTNode>>,
         /// ORDER BY
-        order_by: Option<Vec<ASTNode>>,
+        order_by: Option<Vec<SQLOrderByExpr>>,
         /// GROUP BY
         group_by: Option<Vec<ASTNode>>,
         /// HAVING
@@ -105,7 +105,7 @@ pub enum ASTNode {
         /// WHERE
         selection: Option<Box<ASTNode>>,
         /// ORDER BY
-        order_by: Option<Vec<ASTNode>>,
+        order_by: Option<Vec<SQLOrderByExpr>>,
         limit: Option<Box<ASTNode>>,
     },
     /// CREATE TABLE
@@ -124,6 +124,20 @@ pub struct SQLAssigment {
     value: Box<ASTNode>
 }
 
+/// SQL ORDER BY expression
+#[derive(Debug, Clone, PartialEq)]
+pub struct SQLOrderByExpr {
+    pub expr: Box<ASTNode>,
+    pub asc: bool
+}
+
+impl SQLOrderByExpr {
+    pub fn new(expr: Box<ASTNode>,
+               asc: bool) -> Self {
+        SQLOrderByExpr { expr, asc }
+    }
+}
+
 /// SQL column definition
 #[derive(Debug, Clone, PartialEq)]
 pub struct SQLColumnDef {

src/sqlparser.rs

@@ -563,8 +563,8 @@ impl Parser {
     }
 
     /// Parse a comma-delimited list of SQL ORDER BY expressions
-    pub fn parse_order_by_expr_list(&mut self) -> Result<Vec<ASTNode>, ParserError> {
-        let mut expr_list: Vec<ASTNode> = vec![];
+    pub fn parse_order_by_expr_list(&mut self) -> Result<Vec<SQLOrderByExpr>, ParserError> {
+        let mut expr_list: Vec<SQLOrderByExpr> = vec![];
         loop {
             let expr = self.parse_expr(0)?;
 
@@ -590,10 +590,7 @@ impl Parser {
                 None => true,
             };
 
-            expr_list.push(ASTNode::SQLOrderBy {
-                expr: Box::new(expr),
-                asc,
-            });
+            expr_list.push(SQLOrderByExpr::new(Box::new(expr),asc));
 
             if let Some(t) = self.peek_token() {
                 if t == Token::Comma {
@@ -805,11 +802,11 @@ mod tests {
             ASTNode::SQLSelect { order_by, .. } => {
                 assert_eq!(
                     Some(vec![
-                        ASTNode::SQLOrderBy {
+                        SQLOrderByExpr {
                             expr: Box::new(ASTNode::SQLIdentifier("lname".to_string())),
                             asc: true,
                         },
-                        ASTNode::SQLOrderBy {
+                        SQLOrderByExpr {
                             expr: Box::new(ASTNode::SQLIdentifier("fname".to_string())),
                             asc: false,
                         },