update select from set to list

Author: HazelYuAhiru

core/query_parser.py

@@ -74,7 +74,7 @@ def parse(self, query: str) -> QueryNode:
         )
 
     def parse_select(self, select_list: list) -> SelectNode:
-        items = set()
+        items = []
         for item in select_list:
             if isinstance(item, dict) and 'value' in item:
                 expression = self.parse_expression(item['value'])
@@ -85,11 +85,11 @@ def parse_select(self, select_list: list) -> SelectNode:
                         expression.alias = alias
                     self.aliases[alias] = expression
 
-                items.add(expression)
+                items.append(expression)
             else:
                 # Handle direct expression (string, int, etc.)
                 expression = self.parse_expression(item)
-                items.add(expression)
+                items.append(expression)
 
         return SelectNode(items)
 

tests/test_query_parser.py

@@ -39,7 +39,7 @@ def test_basic_parse():
     count_star = FunctionNode("COUNT", _alias="emp_count", _args=[ColumnNode("*")])
 
     # SELECT clause
-    select_clause = SelectNode({emp_name, dept_name, count_star})
+    select_clause = SelectNode([emp_name, dept_name, count_star])
     # FROM clause with JOIN
     join_condition = OperatorNode(emp_dept_id, "=", dept_id)
     join_node = JoinNode(emp_table, dept_table, JoinType.INNER, join_condition)