MDEV-27229: Estimation for filtered rows less precise ... #5

Followup: remove this line from get_column_range_cardinality()

      set_if_bigger(res, col_stats->get_avg_frequency());

and make sure it is only used with the binary histograms.
For JSON histograms, it makes the estimates unnecessarily imprecise.

sql/opt_range.cc

@@ -3277,7 +3277,10 @@ double records_in_column_ranges(PARAM *param, uint idx,
       break;
     }
     total_rows += rows;
-  }    
+  }
+  if (total_rows == 0)
+    total_rows= MY_MIN(1, param->table->stat_records());
+
   return total_rows;
 }