Note: this isint related to my other thread.<BR><BR>Hey<BR><BR>Im writing a php app to collect statistics about our platform. I have about 40 different count(*) querys to run against a mysql database.
根据某一条件从数据库表中查询 『有』与『没有』,只有两种状态,那为什么在写SQL的时候,还要SELECT count(*) 呢? 无论是刚入道的程序员新星,还是精湛沙场多年的程序员老白,都是一如既往的count 业务代码中,需要根据一个或多个条件,查询是否存在记录 ...