高性能MySQL之Count統計查詢
https://blog.csdn.net/qq_15037231/article/details/81179383
MySQL 大表的count()優化
https://blog.csdn.net/u012674931/article/details/52711137
MySQL count(*),count(1),count(field)區別、性能差異及優化建議
https://mytecdb.com/blogDetail.php?id=81
為什么你是一直認為count(1) 比count(*) 效率高？
http://www.kokojia.com/article/38986.html