1、select 语句 基本格式如下select [列名],[列名]...[或*] from [表名] where 查询条件 group by 分组条件 order by 排序条件
3、用法二，增加条件select * from city where city like '北%'查询所有，city列第一个字是北的数据
5、用法四，对查询的结果按条件排序select SUBSTRING(city,1,1)巳呀屋饔,count(1) from city group by SUBSTRING(city,1,1)order by COUNT(1) desc对上述分组结果，按数据排序，由大到小
