记一个自认为写得有点复杂的sql语句，含义是跨3张表的select：
select table_name,column_name,data_type,data_length,data_scale from user_tab_columns where (data_type != 'NUMBER' or data_length != 22 or data_scale != 6) and (table_name,column_name) in (select upper(a.table_name_eng), upper(b.column_name_eng) from sys_table_info a, sys_column_info b where b.data_type=6 and a.table_id = b.table_id) order by table_name,column_name;