1.按名字分组且获得相同名字的数量
select sname , COUNT(sname) from student1 GROUP BY sname
2.按名字去重
select DISTINCT sname from student1
3
)
//获得最高总工资的部门
select max(t.money) ss,dname FROM(
select d.dname as dname,SUM(s.money) as money FROM ploy1 p,department d,salary1 s WHERE p.did=d.did and p.pid=s.pid GROUP BY d.dname
) t
//获取总金额最低的部门
SELECT bb, MIN(ss) from (select d.dname bb,SUM(money) ss from ploy1 p,department d,salary1 s WHERE p.did=d.did and p.pid=s.pid GROUP BY d.dname) t
//获取工资最低的人员
SELECT pname ,MIN(s.money) FROM ploy1 p,department d,salary1 s WHERE p.did=d.did and p.pid=s.pid
//查询每个月份总额最高的那个
SELECT MAX(t.ss) ,t.months from (SELECT months ,sum(s.money) ss FROM ploy1 p,department d,salary1 s WHERE p.did=d.did and p.pid=s.pid group by s.months) t
//获取每个部门几个月里最低的一个月
select t.dname,min(t.ss) from (SELECT dname,months,sum(money) ss from ploy1 p,department d,salary1 s WHERE p.did=d.did and p.pid=s.pid GROUP BY dname, months) t GROUP BY t.dname