Oracle PL/SQL Tutorial/Numerical Math Functions/to binary double

v_double_nr:= to_binary_double(numeric variable)

SQL>
SQL> set timing on
SQL>
SQL> declare
  2      v_nr number;
  3  begin
  4      for i in 1..1000000 loop
  5          v_nr:=sqrt(i);
  6      end loop;
  7  end;
  8  /
PL/SQL procedure successfully completed.
Elapsed: 00:00:01.54
SQL>
SQL> declare
  2      v_nr binary_float;
  3  begin
  4      for i in 1..1000000 loop
  5          v_nr:=sqrt(to_binary_float(i));
  6      end loop;
  7  end;
  8  /
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.51
SQL>
SQL> set timing off
SQL>