fix(rbo,rules,QA): ExistsFilter::transform merges statistics to enable QA for EXISTS expressions.

dbcon/mysql/ha_exists_sub.cpp

@@ -127,6 +127,9 @@ execplan::ParseTree* ExistsSub::transform()
     return NULL;
   }
 
+  // Insert column statistics
+  fGwip.mergeTableStatistics(gwi.tableStatisticsMap);
+
   // remove outer query tables
   CalpontSelectExecutionPlan::TableList tblist;