Oracle查看表实际占用空间和实际行数

select t.table_name,t.num_rows from user_tables t ORDER BY NUM_ROWS DESC;//实际行数

analyze table emp compute statistics;
select num_rows * avg_row_len
from user_tables
where table_name = 'TB_SYS_LOG';//某一个表占用的空间

analyze table emp compute statistics;
select table_name,num_rows * avg_row_len len
from user_tables order by len desc;//所有表占用的空间