SQL> alter table test_compress compress for all operations; Table altered. SQL> alter table test_compress drop column object_name; Table altered. In 11g it is allowed to drop columns from a compressed table IF compatible is set to 11.1 or higher AND table was created with the "compress for...
sql ALTER TABLE employees DROP COLUMN middle_name; 验证列是否已成功从表中删除: 你可以通过查询表的结构来验证列是否已被成功删除。这可以通过DESC命令或查询ALL_TAB_COLUMNS视图来实现。 sql DESC employees; 或者: sql SELECT COLUMN_NAME FROM ALL_TAB_COLUMNS WHERE TABLE_NAME = 'EMPLOYEES' AND OWNER...
ALTERTABLEsuppliersSETUNUSEDCOLUMNfax;Code language:SQL (Structured Query Language)(sql) From now on, you cannot access thefaxcolumn anymore: SELECT*FROMsuppliers;Code language:SQL (Structured Query Language)(sql) You can view the number of unused columns per table from theDBA_UNUSED_COL_TABSview...
SQL> alter table test_compress compress for all operations; Table altered. SQL> alter table test_compress drop column object_name; Table altered. In 11g it is allowed to drop columns from a compressed table IF compatible is set to 11.1 or higher AND table was created with the "compress for...
我 们要删除表中不用的字段,如果直接drop column,对于大表,进行DDL操作的时间会比较长,会严重阻塞DML语句,导致应用服务器crash,通常的做法是先set unused column column_name 或者 set unused column_name,column_name...,然后再利用停机时间做alter table table_name drop unused columns。
SQL> ALTER TABLE t1 DROP UNUSED COLUMNS; ALTER TABLE t1 DROP UNUSED COLUMNS * ERROR at line 1: ORA-39726: unsupported add/drop column operation on compressed tables SQL> alter table t1 compress for oltp; Table altered. SQL> ALTER TABLE t1 DROP UNUSED COLUMNS; ...
只要有CPU,我想要完成的是启动一个新进程(查询+过滤器+ Parquet持久化)。defdrop_constant_columns( 浏览1提问于2018-05-25得票数0 回答已采纳 2回答 跟踪Oracle中的drop列进度 、、 我在Oracle中对一个巨大的表(1.8TB大小)发出了以下语句:它已经运行了近10天,由于内存不足而崩溃了几次。我继续写道:我如何...
The problem appeared in a thread on the Oracle Developer Forum from someone who was trying to drop a pair of columns and finding that the statement failed with a surprising choice of error: ORA-00904: Invalid Identifier. The surprising thing about this error was that the named identifier was...
drop了sqlserver一个大表image类型的列,感觉作为一个ddl语句应该在drop之后会释放空间,但drop后查询表发现并没有缩小,也不像oracle删除表空间中的表后可以复用原空间,插入数据之后数据文件还在不断增大。 二、 如何让sqlserver drop列后释放空间 法一:重建聚集索引(推荐) ...
Drop和Create table如果存在如果不存在,则在oracle过程中创建 git stash pop和git stash drop之间的区别 Group by值范围和drop重复Hql/Sql中的行 JavaScript drop n drop XY location (由于拖动元素中的点而禁用时)drop n drop XY位置 Oracle ATG和Struts之间的区别?