create table table_count (owner varchar(100),table_name varchar(100),cnt int,size_mb int);
truncate table table_count;

declare
v_owner VARCHAR2(100);
v_tabname VARCHAR2(100);
stmt  VARCHAR2(200);
num_rows number;
begin
    for rec in (select owner,table_name from dba_tables where owner='DEM' order by 1, 2)
    loop
        select rec.owner,rec.table_name into v_owner,v_tabname from dual; 
        stmt := 'select count(*) from "' || v_owner || '"."' || v_tabname || '"';
        EXECUTE IMMEDIATE stmt INTO num_rows;  
        EXECUTE IMMEDIATE 'insert into table_count values('''||v_owner||''','''||v_tabname||
        ''','''||to_number(num_rows)||''','''||table_used_space(v_owner,v_tabname)*32/1024||''')';
    end loop;
end;

select * from table_count order by cnt desc;

确保收集统计信息后，执行下面SQL可以查看行数信息：select table_name,num_rows from user_tables

select owner,table_name,table_rowcount(owner, table_name) aa from dba_tables order by 3 desc;

select table_name,num_rows from user_tables