Shrink table after delete

Question

Hi,
I want to remove some data from a Oracle table, too free up some space on hard drive.
I use delete clause with where condition to delete data, but then after i would need some shrink clause to shrink up the table as i understand.
I cant use truncate because it doesn't allow to use where clause. I need something like:
delete from table 1 where condition1;
shrink table1; --rfree up space                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

Simply deleting rows doesn't make blocks eligible for deallocation. Try this:
truncate table mette reuse storage;
CALL DBMS_STATS.GATHER_TABLE_STATS(USER,'mette');
SELECT t.blocks used, s.blocks allocated
FROM   user_tables t JOIN user_segments s ON s.segment_name = t.table_name
WHERE  t.table_name = 'METTE';
   USED ALLOCATED
      0     20480
alter table mette deallocate unused;
CALL DBMS_STATS.GATHER_TABLE_STATS(USER,'mette');
SELECT t.blocks used, s.blocks allocated
FROM   user_tables t JOIN user_segments s ON s.segment_name = t.table_name
WHERE  t.table_name = 'METTE';
   USED ALLOCATED
      0         8
alter table mette allocate extent;
-- ...same query...
   USED ALLOCATED
      0        16
alter table mette deallocate unused;
-- ...same query...
   USED ALLOCATED
      0         8