MySQL 查找价格最高的图书经销商的几种SQL语句
mysql> use test; Database changed mysql> CREATE TABLE shop ( -> article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL, -> dealer CHAR(2
mysql> use test; Database changed mysql> CREATE TABLE shop ( -> article INT(4) UNSIGNED ZEROFILL DEFAULT '0000' NOT NULL, -> dealer CHAR(2
语法: GROUP_CONCAT([DISTINCT] expr [,expr ...][ORDER BY {unsigned_integer | col_name | expr}[ASC | DESC] [,col_name ...]][SEPARATOR str_val]) 下面演示一下这个函数
Socket(套接字) ◆先看定义: typedef unsigned int u_int; typedef u_int SOCKET; ◆Socket相当于进行网络通信两端的插座,只要对方的Socket和自己的Socket有通信联接,双方就可以发送和接收数据了。其定义类似于文件句柄的定义。 ◆So
相应的数据结构: struct arphdr { unsigned short int ar_hrd; unsigned short int ar_pro; unsigned char ar_hln; unsigned char ar_pln; unsigned short int a