plsql - For Loop in Oracle / Toad -

i new oracle , pl/sql , trying following.

i returning column names table name stored in variable

variable v_table varchar2(100) begin select 'mytable' :v_table dual; end;  select column_name all_tab_columns table_name = :v_table 

this returns rowset

column_name colname1 colname2 colname3 

i loop through returned rowset , stats each column.

select count distinct(colname1), min(colname1), max(colname1) :v_table group min(colname1), max(colname1)  

however cannot figure out how loop through rowset.

by using below can display column names of table , append sql query per requirement...

    declare          v_table varchar2(100):='table_name';          type nt_var1 table of varchar2(30);          typ_nt nt_var1;         begin         select column_name bulk collect typ_nt all_tab_columns table_name =v_table         order column_id;         in 1..typ_nt.count         loop         dbms_output.put_line('column '||i||': '||typ_nt(i));         end loop;         end; 

note: should run select query dynamically means use of execute immediate why because passing table_name @ run time.

edit after editing query in loop below.

 declare          v_table varchar2(100):='table_name';          type nt_var1 table of varchar2(30);          typ_nt nt_var1;          var2 varchar2(2000);          var3 varchar2(2000);         begin         select column_name bulk collect typ_nt all_tab_columns table_name =v_table         order column_id;         in 1..typ_nt.count         loop         dbms_output.put_line('column '||i||': '||typ_nt(i));         execute immediate 'select to_char(min('||typ_nt(i)||')),to_char(max('||typ_nt(i)||')) '||v_table var2,var3;         dbms_output.put_line(var2||' '||var3);         end loop;         end; 

note: find max data length of column present in table , assign same data type var2 , var3 variables.