diff --git a/dbcon/joblist/joblistfactory.cpp b/dbcon/joblist/joblistfactory.cpp
index 66245a8e2..b34215433 100644
--- a/dbcon/joblist/joblistfactory.cpp
+++ b/dbcon/joblist/joblistfactory.cpp
@@ -1525,7 +1525,7 @@ void parseExecutionPlan(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo,
     // bug4531, window function support
     WindowFunctionStep::checkWindowFunction(csep, jobInfo);
 
-    // bug3391, move forward the aggregation check for no aggregte having clause.
+    // bug3391, move forward the aggregation check for no aggregate having clause.
     checkAggregation(csep, jobInfo);
 
     // include filters in having clause, if any.
diff --git a/dbcon/joblist/windowfunctionstep.cpp b/dbcon/joblist/windowfunctionstep.cpp
index 1a603a98e..0c987919a 100644
--- a/dbcon/joblist/windowfunctionstep.cpp
+++ b/dbcon/joblist/windowfunctionstep.cpp
@@ -477,6 +477,17 @@ void WindowFunctionStep::checkWindowFunction(CalpontSelectExecutionPlan* csep, J
         colSet.insert(key);
     }
 
+    // MCOL-3435 We haven't yet checked for aggregate, but we need to know
+    bool hasAggregation = false;
+    for (uint64_t i = 0; i < jobInfo.deliveredCols.size(); i++)
+    {
+        if (dynamic_cast<AggregateColumn*>(jobInfo.deliveredCols[i].get()) != NULL)
+        {
+            hasAggregation = true;
+            break;
+        }
+    }
+
     // add non-duplicate auxiliary columns
     RetColsVector colsInAf;
 
@@ -499,10 +510,30 @@ void WindowFunctionStep::checkWindowFunction(CalpontSelectExecutionPlan* csep, J
             if (colSet.find(key) == colSet.end())
             {
                 jobInfo.deliveredCols.push_back(*j);
-// MCOL-3343 Enable this if we decide to allow Window Functions to run with
-// aggregates with no group by. MariaDB allows this. Nobody else in the world does.
-// There will be more work to get it to function if we try this.                
-//                jobInfo.windowSet.insert(getTupleKey(jobInfo, *j, true));
+                // MCOL-3435 Allow Window Functions to run with aggregates with 
+                // no group by by inserting a group by for window parameters.
+                if (hasAggregation)
+                {
+                    // If an argument is an AggregateColumn, don't group by it.
+                    if (dynamic_cast<AggregateColumn*>(j->get()) == NULL)
+                    {
+                        bool bFound = false;
+                        for (std::vector<SRCP>::iterator igpc = csep->groupByCols().begin(); 
+                                                         igpc < csep->groupByCols().end();
+                                                         ++igpc)
+                        {
+                            if (*igpc->get() == *j->get())
+                            {
+                                bFound = true;
+                                break;
+                            }
+                        }
+                        if (!bFound)
+                        {
+                            csep->groupByCols().push_back(*j);
+                        }
+                    }
+                }
             }
 
             colSet.insert(key);