mysql之distinct与group_by
distinct
select distinct name from user;
group by
select * from user group by name;
PS: 对于经过 group 后的条件筛选使用 having (where 作用与 group 前)
select distinct name from user;
select * from user group by name;
PS: 对于经过 group 后的条件筛选使用 having (where 作用与 group 前)