Fix bug #12779 : never give a row count estimate of 0 to the MySQL query optimizer, as then left join optimizer may beleive it KNOWS that the table is empty; note that this fix may change query optimization of many other queries where one table is empty; note that the proper fix would be to make the query optimizer to know that the row count estimates it receives really are just estimates, it cannot assume they are certain


sql/ha_innodb.cc:
  Fix bug #12779 : never give a row count estimate of 0 to the MySQL query optimizer, as then left join optimizer may beleive it KNOWS that the table is empty; note that this fix may change query optimization of many other queries where one table is empty; note that the proper fix would be to make the query optimizer to know that the row count estimates it receives really are just estimates, it cannot assume they are certain