create table student(id int ,name string);
create table log(id INT,text string) partitioned by (year string);
log表有id和text列，还有一个year的虚拟列
默认情况下，表被设定为文本内容格式并且是有^A也就是ctrl-a来分割
show tables;
+-----------+--+
| tab_name |
+-----------+--+
| log |
| student |
| xx |
+-----------+--+
show tables '.*';
+-----------+--+
| tab_name |
+-----------+--+
| log |
| student |
| xx |
+-----------+--+
show tables '*ent';
+-----------+--+
| tab_name |
+-----------+--+
| student |
+-----------+--+
describe log;
+--------------------------+-----------------------+-----------------------+--+
| col_name | data_type | comment |
+--------------------------+-----------------------+-----------------------+--+
| id | int | |
| text | string | |
| year | string | |
| | NULL | NULL |
| # Partition Information | NULL | NULL |
| # col_name | data_type | comment |
| | NULL | NULL |
| year | string | |
+--------------------------+-----------------------+-----------------------+--+
8 rows selected (0.144 seconds)
alter table log rename to log_table;
alter table log_table add columns (date string);
alter table log_table add columns(comment string comment 'a comment');
describe log_table;
+--------------------------+-----------------------+-----------------------+--+
| col_name | data_type | comment |
+--------------------------+-----------------------+-----------------------+--+
| id | int | |
| text | string | |
| date | string | |
| comment | string | a comment |
| year | string | |
| | NULL | NULL |
| # Partition Information | NULL | NULL |
| # col_name | data_type | comment |
| | NULL | NULL |
| year | string | |
+--------------------------+-----------------------+-----------------------+--+
10 rows selected (0.153 seconds)
alter table log_table replace columns(comment string comment 'two comment');
describe log_table;
+--------------------------+-----------------------+-----------------------+--+
| col_name | data_type | comment |
+--------------------------+-----------------------+-----------------------+--+
| comment | string | two comment |
| year | string | |
| | NULL | NULL |
| # Partition Information | NULL | NULL |
| # col_name | data_type | comment |
| | NULL | NULL |
| year | string | |
+--------------------------+-----------------------+-----------------------+--+
7 rows selected (0.118 seconds)
replace执行之后表的所有列会被替换为新指定的这些列，分区没有被替换
drop table log_table;
No rows affected (0.717 seconds)