How do I perform specific searches on data, such as: find the students whose grades are in the top 30% of a class?

Assume there is a student grade table: student(name char(10),score int); To find out the top 30% of students in the class by using the following commands:

dmSQL> create temp table tt1 (

    2>   c1 serial(1),

    3>   name char(10),

    4>   score int

    5> );

dmSQL> select *

    2>   from student

    3>   group by score, name

    4>   into tt1 (name,score);

dmSQL> select name,score

    2>   from tt1

    3>   where c1 (

    4>     select count(c1)*0.7

    5>       from tt1

    6>   )

    7>   order by score desc;

Caution: Every time you execute these commands, you have to rebuild temp table tt1.