mysql> select name from test where name = any(select name from test where chengji > 80 and xueke='guangdong') and chengji >80 and xueke ='hunan'; sel... Read More
半年前,我写了《计算机是如何启动的?》,探讨BIOS和主引导记录的作用。那篇文章不涉及操作系统,只与主板的板载程序有关。今天,我想接着往下写,探讨操作系统接管硬件以后发生的事情,也就是操作系统的启动流程。这个部分比较有意思。因为在BIOS阶段,计算机的行为基本上被写死了,程序员可以做的事情并不多;但... Read More
1、三个表连接SELECT * FROM stock320151203 as a , stock320151202 as b , stock320151201 as c WHERE a.id=b.id and a.id=c.id;两个表连接:SELECT * FROM stock320151203 ... Read More