要查询Oracle下某一个用户下所有表的记录条数，可以采用如下办法：
1、创建function count_tables_rows
create or replace function count_table_rows(table_name in varchar2,
owner in varchar2 default null)
return number authid current_user IS
num_rows number;
stmt varchar2(2000);
begin
if owner is null then
stmt := 'select count(*) from "' || table_name || '"';
else
stmt := 'select count(*) from "' || owner || '"."' || table_name || '"';
end if;
execute immediate stmt
into num_rows;
return num_rows;
end;
2、使用sql语句查询
select table_name, count_table_rows(table_name) nrows
from user_tables
order by nrows desc
通过以上两个步骤，即可查询出某一用户下所有表的记录数据集合。