数据定义语言:(DDL)
建表语句:
CREATE TABLE [IF NOT EXISTS] table_name
[(col_name data_type [COMMENT col_comment], ...)] // 设置表的字段,给字段添加注释
[COMMENT table_comment] //给建的表添加注释
[PARTITIONED BY (col_name data_type [COMMENT col_comment], ...)] //添加分区,目前分区标只能是string类型的;
[LIFECYCLE days] //设置表的生命周期
[AS select_statement] //也可以用as方式建表,但是as和第一个的col方式是不能并存的
删表:
drop table [if exists] table_name;
修改表名:
alter table table_name rename to new_table_name;
分区操作:
添加分区:
alter table table_name add [if not exists] partition(partition_col1 = partition_col_value1, partition_col2 = partiton_col_value2, ...);
删除分区:
alter table table_name drop [if exists] partition(partition_col1 = partition_col_value1, partition_col2 = partiton_col_value2, ...);
修改属性:
添加列:
ALTER TABLE table_name ADD COLUMNS (col_name1 type1,col_name2 type2...);
修改列名:
ALTER TABLE table_name CHANGE COLUMN old_col_name RENAME TO new_col_name;
修改表注释:
alter table table_name set comment 'tb1 comment'
修改列/分区注释:
ALTER TABLE table_name CHANGE COLUMN col_name COMMENT comment_string;
DDL数据定义语言案例演示:
创建/删除普通表:
odps@ sdrtest>create table t_people (id bigint , name string); //创建普通表 odps@ sdrtest>desc t_people; //查看普通表的表结构 +------------------------------------------------------------------------------------+
| Owner: ALIYUN$1399438812@qq.com | Project: sdrtest |
| TableComment: |
+------------------------------------------------------------------------------------+
| CreateTime: 2019-04-13 09:02:41 |
| LastDDLTime: 2019-04-13 09:02:41 |
| LastModifiedTime: 2019-04-13 09:02:41 |
+------------------------------------------------------------------------------------+
| InternalTable: YES | Size: 0 |
+------------------------------------------------------------------------------------+
| Native Columns: |
+------------------------------------------------------------------------------------+
| Field | Type | Label | Comment |
+------------------------------------------------------------------------------------+
| id | bigint | | |
| name | string | | |
+------------------------------------------------------------------------------------+ OK
odps@ sdrtest>drop table t_people_p; //删除普通表
创建分区表:
odps@ sdrtest>create table t_people_p (id bigint,name string) partitioned by (gender string); //创建分区表 odps@ sdrtest>desc t_people_p; //查看表结构 +------------------------------------------------------------------------------------+
| Owner: ALIYUN$1399438812@qq.com | Project: sdrtest |
| TableComment: |
+------------------------------------------------------------------------------------+
| CreateTime: 2019-04-13 09:08:53 |
| LastDDLTime: 2019-04-13 09:08:53 |
| LastModifiedTime: 2019-04-13 09:08:53 |
+------------------------------------------------------------------------------------+
| InternalTable: YES | Size: 0 |
+------------------------------------------------------------------------------------+
| Native Columns: |
+------------------------------------------------------------------------------------+
| Field | Type | Label | Comment |
+------------------------------------------------------------------------------------+
| id | bigint | | |
| name | string | | |
+------------------------------------------------------------------------------------+
| Partition Columns: |
+------------------------------------------------------------------------------------+
| gender | string | |
+------------------------------------------------------------------------------------+ OK
增加/删除分区表中的分区:
odps@ sdrtest>alter table t_people_p add partition (gender = 'male'); //增加分区
odps@ sdrtest>alter table t_people_p drop if exists partition (gender = 'male'); //删除已有分区
修改表属性:
odps@ sdrtest>alter table t_people set lifecycle 7; //修改表的lifecycle属性为7天; 查看表结构验证:
odps@ sdrtest>desc t_people; +------------------------------------------------------------------------------------+
| Owner: ALIYUN$1399438812@qq.com | Project: sdrtest |
| TableComment: |
+------------------------------------------------------------------------------------+
| CreateTime: 2019-04-13 09:02:41 |
| LastDDLTime: 2019-04-13 09:02:41 |
| LastModifiedTime: 2019-04-13 09:02:41 |
| Lifecycle: 7 | //验证为lifecycle里面的属性确定被修改为了7天;
+------------------------------------------------------------------------------------+
| InternalTable: YES | Size: 0 |
+------------------------------------------------------------------------------------+
| Native Columns: |
+------------------------------------------------------------------------------------+
| Field | Type | Label | Comment |
+------------------------------------------------------------------------------------+
| id | bigint | | |
| name | string | | |
+------------------------------------------------------------------------------------+ OK
给表格新增一列:
odps@ sdrtest>alter table t_people add columns (age bigint); odps@ sdrtest>desc t_people; +------------------------------------------------------------------------------------+
| Owner: ALIYUN$1399438812@qq.com | Project: sdrtest |
| TableComment: |
+------------------------------------------------------------------------------------+
| CreateTime: 2019-04-13 09:02:41 |
| LastDDLTime: 2019-04-13 09:20:09 |
| LastModifiedTime: 2019-04-13 09:02:41 |
| Lifecycle: 7 |
+------------------------------------------------------------------------------------+
| InternalTable: YES | Size: 0 |
+------------------------------------------------------------------------------------+
| Native Columns: |
+------------------------------------------------------------------------------------+
| Field | Type | Label | Comment |
+------------------------------------------------------------------------------------+
| id | bigint | | |
| name | string | | |
| age | bigint | | |
+------------------------------------------------------------------------------------+ OK
修改表名:
odps@ sdrtest>alter table t_people rename to t_women;
查看修改结果:
odps@ sdrtest>list tables;
ALIYUN$1399438812@qq.com:t_women
更新列名:
odps@ sdrtest>ALTER TABLE t_women CHANGE COLUMN age RENAME TO age1; //将age列名更新为age1 odps@ sdrtest>desc t_women; +------------------------------------------------------------------------------------+
| Owner: ALIYUN$1399438812@qq.com | Project: sdrtest |
| TableComment: |
+------------------------------------------------------------------------------------+
| CreateTime: 2019-04-13 09:02:41 |
| LastDDLTime: 2019-04-13 09:28:02 |
| LastModifiedTime: 2019-04-13 09:02:41 |
| Lifecycle: 7 |
+------------------------------------------------------------------------------------+
| InternalTable: YES | Size: 0 |
+------------------------------------------------------------------------------------+
| Native Columns: |
+------------------------------------------------------------------------------------+
| Field | Type | Label | Comment |
+------------------------------------------------------------------------------------+
| id | bigint | | |
| name | string | | |
| age1 | bigint | | | //验证列名已经更新;
+------------------------------------------------------------------------------------+ OK
others:...