sql 分组取第一且求均值

表结构
create table grade
(
id int primary key auto_increment,
gradegive varchar(50),
gradereceive varchar(50),
gradedeptId int,
grade double,
total double,
sort int,
term varchar(50)
);
请问：我想根据sort分组，取出每一组grade的平均值和gradedeptid（可不同）的任何一个值（可是第一个），SQL语句具体该怎么写？
不胜感激！！！！

select avg(grade),max(gradedeptid) from grade group by sort
按照此类方法，应从我的数据库中取出2条数据
可是下面方法之读取了一条数据，当要第二次读取max(gradedeptid)时卡死，CPU不停地高速运行
while(rs1.next()){
int sort = rs1.getInt("sort");
double score = rs1.getDouble("grade");
int give = rs1.getInt("gradedeptid"); //第二次到这了就卡死了
afloor = ind.getFloor(give);
sv.setTotal(sv.getTotal() + score);
if(sort > 0){
//略
}else if(sort==-1 || sort==-2){
sv.setPeople(sv.getPeople() + score);
}else if(sort <= -3){
int rid = -sort;
sql2 = "select sort from results where id="+rid;
rs2 = DB.getResultSet(stmt2, sql2);
while(rs2.next()){
int rsort = rs2.getInt("sort");
if(rsort==0){
sv.setPeople(sv.getPeople() + score);
}else if(rsort==1){
sv.setSecty(sv.getSecty() + score);
}else if(rsort==2){
sv.setExtra(sv.getExtra() + score);
}
}
}
}

select avg(grade),max(gradedeptid) from grade group by sort
分组取出grade平均值和gradedeptid最大值

select sort,avg(grade),max(gradedeptid) from grade group by sort

Select avg(garde) As avaGrade, min(gradedeotid) As gradedeotid From grade Group by sort