数据库SQL语句 --- 分组查询(八)

1.group by:可用于单个字段分组，也可用于多个字段分组

select gender from students group by gender;

select gender,name from students group by gender,name;

2.group_concat(字段名):统计每个分组指定字段的信息集合，每个信息之间使用逗号分隔

select gender,group_concat(name) from students group by gender;

3.having：分组数据过滤使用having

select gender,group_concat(name) from students group by gender having count(*)>2;