mysql查询各系的学生人数,列名称显示为:系部编号,学生人数mysql查询各系的学生人数,列名称显示为:系部编号,学生人数mysql查询各系的学生人数,列名称显示为:系部编号,学生人数
select count(1) from student group by 专业字段
select sname, sgender, count(sid) cnt from student group by sname, sgender having cnt>1;