SQL

plsql to generate all combinations of specified number of characters in string

SQL> declare

  2    cn_string constant varchar2(3) := 'HER';

  3  begin

  4    for i in 1..3

  5    loop

  6      for j in 1..3

  7      loop

  8        for k in 1..3

  9        loop

 10          if    i != j

 11            and j != k

 12            and k != i

 13          then

 14            dbms_output.put_line

 15            ( substr(cn_string,i,1) ||

 16              substr(cn_string,j,1) ||

 17              substr(cn_string,k,1)

 18            );

 19          end if;

 20        end loop;

 21      end loop;

 22    end loop;

 23  end;

 24  /

HER

HRE

EHR

ERH

RHE

REH