501d7f
@@ -4643,8 +4643,8 @@
private Operator genGroupByPlanMapGroupByOperator(QB qb,
       ExprNodeDesc grpByExprNode = genExprNodeDesc(grpbyExpr,
           groupByInputRowResolver);
 
-      if (ExprNodeDescUtils.indexOf(grpByExprNode, groupByKeys) >= 0) {
-        // Skip duplicated grouping keys
+      if ((grpByExprNode instanceof ExprNodeColumnDesc) && ExprNodeDescUtils.indexOf(grpByExprNode, groupByKeys) >= 0) {
+        // Skip duplicated grouping keys, it happens when define column alias.
         grpByExprs.remove(i--);
         continue;
       }
