统计用户占用多大的空间，一行数据超过4k

--统计用户占用多大的空间

select sum(bytes)/1024/1024 from user_extents;

select sum(bytes)/1024/1024 from dba_extents;

--一行数据超过4k

select * from (select sum(b.DATA_LENGTH) as sum,b.TABLE_NAME from user_tab_columns b  group by b.TABLE_NAME ) where sum>=4000