HIVE ALTER TABLE Statement
This command is used to add new columns to the end of existing column.
Syntax:
ALTER TABLE <tablename> ADD COLUMNS (
column1 datatype [COMMENT tablecomment],
column2 datatype [COMMENT tablecomment],
...
columnN datatype [COMMENT tablecomment]);
Example:
ALTER TABLE Employee ADD COLUMNS (
designation string COMMENT 'Employee designation',
age int COMMENT 'Employee Age');
ALTER TABLE - Replace Column
This command is used to remove all the existing column and replace it with the new columns specified.
Syntax:
ALTER TABLE <tablename> REPLACE COLUMNS (
column1 datatype [COMMENT tablecomment],
column2 datatype [COMMENT tablecomment],
...
columnN datatype [COMMENT tablecomment]);
Example:
ALTER TABLE Employee REPLACE COLUMNS (
employee_id string COMMENT 'Employee id',
first_name string COMMENT 'Employee First name',
ALTER TABLE - Renaming Table
This command is used to rename the table name to a new one.
Syntax:
ALTER TABLE<tablename> RENAME TO <new_tablename>
Example:
ALTER TABLE Employee RENAME TO NewEmployee
