对于数据库来说多多少少要掌握一点，首先基本的SQL语句要了解。下面来总结一些入门级别的SQL语句。
create相关
•show database; 显示出现有的数据库
•use database_x; 现在要使用数据库database_x
•create table coffee (id int(5) not null,coffee_name varchar(25)); 创建一张表，包含id和coffee_name两个字段
•alter table coffee add taste varchar(10); 增加新的一列
•insert into coffee (id,coffee_name,taste,rank) value ("1","BlueMountain"，“well”，“5”); 插入数据
•show columns from coffee; 查看表结构
•show create table coffee; 查看表信息，包括建表语句
•alter table student rename ss; 改变表名
•alter table ss drop mark; 删除表ss中mark列
select语句
•select * from coffee where id="1"; 查询出id=1的所有信息
•select coffee_name from coffee where id="2"; 查询出id=2的coffee name
•select * from club where id between "1" and "3"; 查询出id=1到3的条目
•select * from club where id="1" or id="3"; 查询出id=1和id=3这两个条目
•select club_name from club where mark>50; 查询出mark大于50的club
•select club_name from club where mark not between 48 and 50; 查询mark不在48与50之间的club
•select * from club where id in("1","3","4"); 查询id=1,3,4的条目
•select * from club where id not in("1","3","4");
•select * from club where name like "M%r"; 通配符%表示任意长度的字符(可以是0，汉字为两个字符)
•select * from club where name like "M_r"; _表示单个字符
•select * from club where id in("1","3","4") and mark>50; 多重查询
•select * from club order by mark desc; 按照mark降序排列(desc：降序，usc：升序)
数量查询相关
•select count(*) from club; 查询club中有多少条记录
•select count(distinct mark) from club; 不同分数的有多少条记录
•select sum(mark) from club; 积分总和
•select avg(mark) from club; 平均积分
•select max(mark) from club; 最高积分
•select min(mark) from club; 最低积分
update语句
•update club set mark=mark-8 where id="1"; id=1的俱乐部积分罚8分
delete语句
•delete from club where id="001"; 删除id=001的俱乐部信息
以上语句都是SQL语句增删改查最基本的部分，属于入门级别，一定要掌握。
