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MySQL数据库语句,计算某一列的和用select sum(b) from a就可以了。
下面来补充一些MySql的基本操作命令。
注: <>表示参数、[]表示可选项
连接数据库:mysql> mysql -u -p;
显示所有数据库:mysql> show databases;
选择数据库:mysql> use ;
创建一个数据库:mysql> create database [charset ];
删除一个数据库:mysql> drop database ;
修改数据库名:mysql无法直接修改数据库名!
显示所有表:mysql> show tables;
删除一张表:mysql> drop table
修改表名:mysql> rename table
清空表:mysql> truncate
truncate和delete的区别:truncate相当于删表再重建一张相同结构的表,操作后得到一张全新表;delete只是删除数据,而且是按照行来删除,如果表中有自增型字段,其影响还在。
查看表结构:mysql> desc
快速建一张相似的表:mysql> create table