i want to add a TINYINT(1) field to a large table (over 10 million record). this field in over than 70% of records (7 million) have not any value.
i wonder should i set the default value as NULL or 0? is it any considerable difference between 0 & NULL in terms of performance and size of table(i mean size on disk).
which one is better to have in this table? 7 million NULL or 7 million 0?