表

1.创建表

create [external] table [if not exists] table_name 
(col_name data_type)
[partitioned by col_name data_type]  
[clustered by col_name,col_name]
[sorted by col_name] into num_buckets buckets]
[row format]
[stored as file_format]
[tblproperties]
[tblproperties]
[location hdfs_path]

2.修改表

（1）重命名表
alter table student rename to student2;

（2）增加列信息:columns
alter table student add columns(age int);

（3）替换列信息:columns,替换表中的所有字段
alter table student replace columns (score double);

（4）修改列信息:column

--只修改列名
alter table student change column name student_name string;
--只修改数据类型
alter table student change column name name int;
--列名和数据类型都修改
alter table student change column name student_name int;

(5)删除列信息
alter table teacher drop column salary

 3.删除表（只能删除内部表，不能删除外部表）

drop：同时删除表所有数据和表结构

truncat：删除表所有数据，不删除表结构

delete:删除表中的行数据

drop table student;

truncate table student;

delete from student where name='test'