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

A: 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.