[GitHub] [calcite] hsyuan commented on a change in pull request #1985: [CALCITE-4011] Implement trait propagation for EnumerableProject…

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hsyuan commented on a change in pull request #1985:
URL: https://github.com/apache/calcite/pull/1985#discussion_r428387288



##########
File path: core/src/test/resources/org/apache/calcite/test/TopDownOptTest.xml
##########
@@ -35,6 +35,46 @@ EnumerableLimit(fetch=[5])
   EnumerableSortedAggregate(group=[{3}], EXPR$1=[COUNT()])
     EnumerableSort(sort0=[$3], dir0=[DESC-nulls-last])
       EnumerableTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+        </Resource>
+    </TestCase>
+    <TestCase name="testSortProject">
+        <Resource name="sql">
+            <![CDATA[select mgr from sales.emp order by mgr desc nulls last]]>
+        </Resource>
+        <Resource name="planBefore">
+            <![CDATA[
+LogicalSort(sort0=[$0], dir0=[DESC-nulls-last])
+  LogicalProject(MGR=[$3])
+    LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+        </Resource>
+        <Resource name="planAfter">
+            <![CDATA[
+EnumerableProject(MGR=[$3])
+  EnumerableSort(sort0=[$3], dir0=[DESC-nulls-last])
+    EnumerableTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+        </Resource>
+    </TestCase>
+    <TestCase name="testSortFilter">
+        <Resource name="sql">
+            <![CDATA[select mgr from sales.emp where deptno > 10 order by mgr desc]]>
+        </Resource>
+        <Resource name="planBefore">
+            <![CDATA[
+LogicalSort(sort0=[$0], dir0=[DESC])
+  LogicalProject(MGR=[$3])
+    LogicalFilter(condition=[>($7, 10)])
+      LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+        </Resource>
+        <Resource name="planAfter">
+            <![CDATA[
+EnumerableProject(MGR=[$3])
+  EnumerableSort(sort0=[$3], dir0=[DESC])
+    EnumerableFilter(condition=[>($7, 10)])
+      EnumerableTableScan(table=[[CATALOG, SALES, EMP]])

Review comment:
       That makes sense, because it is cheaper.
   Let's think it another way.
   ```
   select a, b, c 
     from (select a, b, max(c) c from foo group by a, b) as t 
     where a+b+c>1 
   order by b desc, a desc;
   ```




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