Merge pull request #9823 from ClickHouse/fix-expression-transform-for-empty-totals

Fix Expression transform for empty totals.

dbms/src/Processors/Transforms/ExpressionTransform.cpp

@@ -29,7 +29,7 @@ void ExpressionTransform::transform(Chunk & chunk)
         if (expression->resultIsAlwaysEmpty())
         {
             stopReading();
-            chunk = Chunk(getOutputPort().getHeader().getColumns(), 0);
+            chunk.clear();
             return;
         }
     }

dbms/src/Processors/Transforms/InflatingExpressionTransform.cpp

@@ -28,7 +28,7 @@ void InflatingExpressionTransform::transform(Chunk & chunk)
         if (expression->resultIsAlwaysEmpty())
         {
             stopReading();
-            chunk = Chunk(getOutputPort().getHeader().getColumns(), 0);
+            chunk.clear();
             return;
         }
     }

dbms/tests/queries/0_stateless/02001_empty_join_and_totals.sql

+select * from system.one t1
+join system.one t2
+on t1.dummy = t2.dummy
+limit 0
+FORMAT TabSeparated;
+
+select * from system.one t1
+join system.one t2
+on t1.dummy = t2.dummy
+where t2.dummy > 0
+FORMAT TabSeparated;