docs/sql-ref-syntax-ddl-alter-table.md

---
layout: global
title: ALTER TABLE
displayTitle: ALTER TABLE
license: |
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  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
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  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
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---

### Description

`ALTER TABLE` statement changes the schema or properties of a table.

### RENAME 

`ALTER TABLE RENAME TO` statement changes the table name of an existing table in the database. The table rename command cannot be used to move a table between databases, only to rename a table within the same database.

If the table is cached, the commands clear cached data of the table. The cache will be lazily filled when the next time the table is accessed. Additionally:
  * the table rename command uncaches all table's dependents such as views that refer to the table. The dependents should be cached again explicitly.
  * the partition rename command clears caches of all table dependents while keeping them as cached. So, their caches will be lazily filled when the next time they are accessed.

#### Syntax

```sql
ALTER TABLE table_identifier RENAME TO table_identifier

ALTER TABLE table_identifier partition_spec RENAME TO partition_spec
```

#### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **partition_spec**

    Partition to be renamed. Note that one can use a typed literal (e.g., date'2019-01-02') in the partition spec.

    **Syntax:** `PARTITION ( partition_col_name  = partition_col_val [ , ... ] )`

### ADD COLUMNS

`ALTER TABLE ADD COLUMNS` statement adds mentioned columns to an existing table.

#### Syntax

```sql
ALTER TABLE table_identifier ADD COLUMNS ( col_spec [ , ... ] )
```

#### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **COLUMNS ( col_spec )**

    Specifies the columns to be added.

### DROP COLUMNS

`ALTER TABLE DROP COLUMNS` statement drops mentioned columns from an existing table.
Note that this statement is only supported with v2 tables.

#### Syntax

```sql
ALTER TABLE table_identifier DROP { COLUMN | COLUMNS } [ ( ] col_name [ , ... ] [ ) ]
```

#### Parameters

* **table_identifier**

  Specifies a table name, which may be optionally qualified with a database name.

  **Syntax:** `[ database_name. ] table_name`

* **col_name**

  Specifies the name of the column.

### RENAME COLUMN

`ALTER TABLE RENAME COLUMN` statement changes the column name of an existing table.
Note that this statement is only supported with v2 tables.

#### Syntax

```sql
ALTER TABLE table_identifier RENAME COLUMN col_name TO col_name
```

#### Parameters

* **table_identifier**

  Specifies a table name, which may be optionally qualified with a database name.

  **Syntax:** `[ database_name. ] table_name`

* **col_name**

  Specifies the name of the column.

### ALTER OR CHANGE COLUMN

`ALTER TABLE ALTER COLUMN` or `ALTER TABLE CHANGE COLUMN` statement changes column's definition.

#### Syntax

```sql
ALTER TABLE table_identifier { ALTER | CHANGE } [ COLUMN ] col_name alterColumnAction
```

#### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **col_name**

    Specifies the name of the column.

* **alterColumnAction**

    Change column's definition.

### REPLACE COLUMNS

`ALTER TABLE REPLACE COLUMNS` statement removes all existing columns and adds the new set of columns.
Note that this statement is only supported with v2 tables.

#### Syntax

```sql
ALTER TABLE table_identifier [ partition_spec ] REPLACE COLUMNS  
  [ ( ] qualified_col_type_with_position_list [ ) ]
```

#### Parameters

* **table_identifier**

  Specifies a table name, which may be optionally qualified with a database name.

  **Syntax:** `[ database_name. ] table_name`

* **partition_spec**

  Partition to be replaced. Note that one can use a typed literal (e.g., date'2019-01-02') in the partition spec.

  **Syntax:** `PARTITION ( partition_col_name  = partition_col_val [ , ... ] )`

* **qualified_col_type_with_position_list**

  The list of the column(s) to be added

  **Syntax:** `col_name col_type [ col_comment ] [ col_position ] [ , ... ]`

### ADD AND DROP PARTITION

#### ADD PARTITION

`ALTER TABLE ADD` statement adds partition to the partitioned table.

If the table is cached, the command clears cached data of the table and all its dependents that refer to it. The cache will be lazily filled when the next time the table or the dependents are accessed.

##### Syntax

```sql
ALTER TABLE table_identifier ADD [IF NOT EXISTS] 
    ( partition_spec [ partition_spec ... ] )
```
     
##### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **partition_spec**

    Partition to be added. Note that one can use a typed literal (e.g., date'2019-01-02') in the partition spec.

    **Syntax:** `PARTITION ( partition_col_name  = partition_col_val [ , ... ] )`

#### DROP PARTITION

`ALTER TABLE DROP` statement drops the partition of the table.

If the table is cached, the command clears cached data of the table and all its dependents that refer to it. The cache will be lazily filled when the next time the table or the dependents are accessed.

##### Syntax

```sql
ALTER TABLE table_identifier DROP [ IF EXISTS ] partition_spec [PURGE]
```
     
##### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **partition_spec**

    Partition to be dropped. Note that one can use a typed literal (e.g., date'2019-01-02') in the partition spec.

    **Syntax:** `PARTITION ( partition_col_name  = partition_col_val [ , ... ] )`

#### CLUSTER BY

`ALTER TABLE CLUSTER BY` command can also be used for changing or removing the clustering columns for existing tables.

##### Syntax

```sql
-- Changing Clustering Columns
ALTER TABLE table_identifier CLUSTER BY ( col_name [ , ... ] )

-- Removing Clustering Columns
ALTER TABLE table_identifier CLUSTER BY NONE
```

#### Parameters

* **table_identifier**

  Specifies a table name, which may be optionally qualified with a database name.

  **Syntax:** `[ database_name. ] table_name`

* **col_name**

  Specifies the name of the column.
     
### SET AND UNSET

#### SET PROPERTIES

`ALTER TABLE SET` command is used for setting the table properties. If a particular property was already set, 
this overrides the old value with the new one.

##### Syntax

```sql
-- Set Properties
ALTER TABLE table_identifier SET TBLPROPERTIES ( key1 = val1, key2 = val2, ... )
```

#### UNSET PROPERTIES

`ALTER TABLE UNSET` command is used to drop the table property.

**Note:** If the specified property key does not exist, whether specify `IF EXISTS` or not, the command will ignore it and finally succeed.

##### Syntax

```sql
-- Unset Properties
ALTER TABLE table_identifier UNSET TBLPROPERTIES ( key1, key2, ... )
```

#### SET SERDE

`ALTER TABLE SET` command is used for setting the SERDE or SERDE properties in Hive tables. If a particular property was already set, this overrides the old value with the new one.

##### Syntax

```sql
-- Set SERDE Properties
ALTER TABLE table_identifier [ partition_spec ]
    SET SERDEPROPERTIES ( key1 = val1, key2 = val2, ... )

ALTER TABLE table_identifier [ partition_spec ] SET SERDE serde_class_name
    [ WITH SERDEPROPERTIES ( key1 = val1, key2 = val2, ... ) ]
```

#### SET LOCATION And SET FILE FORMAT

`ALTER TABLE SET` command can also be used for changing the file location and file format for 
existing tables. 

If the table is cached, the `ALTER TABLE .. SET LOCATION` command clears cached data of the table and all its dependents that refer to it. The cache will be lazily filled when the next time the table or the dependents are accessed.

##### Syntax

```sql
-- Changing File Format
ALTER TABLE table_identifier [ partition_spec ] SET FILEFORMAT file_format

-- Changing File Location
ALTER TABLE table_identifier [ partition_spec ] SET LOCATION 'new_location'
```

#### Parameters

* **table_identifier**

    Specifies a table name, which may be optionally qualified with a database name.

    **Syntax:** `[ database_name. ] table_name`

* **partition_spec**

    Specifies the partition on which the property has to be set. Note that one can use a typed literal (e.g., date'2019-01-02') in the partition spec.

    **Syntax:** `PARTITION ( partition_col_name  = partition_col_val [ , ... ] )`

* **SERDEPROPERTIES ( key1 = val1, key2 = val2, ... )**

    Specifies the SERDE properties to be set.

### RECOVER PARTITIONS

`ALTER TABLE RECOVER PARTITIONS` statement recovers all the partitions in the directory of a table and updates the Hive metastore.
Another way to recover partitions is to use `MSCK REPAIR TABLE`.

#### Syntax

```sql
ALTER TABLE table_identifier RECOVER PARTITIONS
```

#### Parameters

* **table_identifier**

  Specifies a table name, which may be optionally qualified with a database name.

  **Syntax:** `[ database_name. ] table_name`

### Examples

```sql
-- RENAME table 
DESC student;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

ALTER TABLE Student RENAME TO StudentInfo;

-- After Renaming the table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

-- RENAME partition

SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=10|
|   age=11|
|   age=12|
+---------+

ALTER TABLE default.StudentInfo PARTITION (age='10') RENAME TO PARTITION (age='15');

-- After renaming Partition
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
+---------+

-- Add new columns to a table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

ALTER TABLE StudentInfo ADD columns (LastName string, DOB timestamp);

-- After Adding New columns to the table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|               LastName|   string|   NULL|
|                    DOB|timestamp|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

-- Drop columns of a table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|               LastName|   string|   NULL|
|                    DOB|timestamp|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

ALTER TABLE StudentInfo DROP columns (LastName, DOB);

-- After dropping columns of the table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

-- Rename a column of a table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|                   name|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

ALTER TABLE StudentInfo RENAME COLUMN name TO FirstName;

-- After renaming a column of the table
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|              FirstName|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

-- ALTER OR CHANGE COLUMNS
DESC StudentInfo;
+-----------------------+---------+-------+
|               col_name|data_type|comment|
+-----------------------+---------+-------+
|              FirstName|   string|   NULL|
|                 rollno|      int|   NULL|
|                    age|      int|   NULL|
|# Partition Information|         |       |
|             # col_name|data_type|comment|
|                    age|      int|   NULL|
+-----------------------+---------+-------+

ALTER TABLE StudentInfo ALTER COLUMN FirstName COMMENT "new comment";

-- After ALTER or CHANGE COLUMNS
DESC StudentInfo;
+-----------------------+---------+-----------+
|               col_name|data_type|    comment|
+-----------------------+---------+-----------+
|              FirstName|   string|new comment|
|                 rollno|      int|       NULL|
|                    age|      int|       NULL|
|# Partition Information|         |           |
|             # col_name|data_type|    comment|
|                    age|      int|       NULL|
+-----------------------+---------+-----------+

-- REPLACE COLUMNS
DESC StudentInfo;
+-----------------------+---------+-----------+
|               col_name|data_type|    comment|
+-----------------------+---------+-----------+
|              FirstName|   string|new comment|
|                 rollno|      int|       NULL|
|                    age|      int|       NULL|
|# Partition Information|         |           |
|             # col_name|data_type|    comment|
|                    age|      int|       NULL|
+-----------------------+---------+-----------+

ALTER TABLE StudentInfo REPLACE COLUMNS (name string, ID int COMMENT 'new comment');

-- After replacing COLUMNS
DESC StudentInfo;
+-----=---------+---------+-----------+
|       col_name|data_type|    comment|
+---------------+---------+-----------+
|           name|   string|       NULL|
|             ID|      int|new comment|
| # Partitioning|         |           |
|Not partitioned|         |           |
+---------------+---------+-----------+

-- Add a new partition to a table 
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
+---------+

ALTER TABLE StudentInfo ADD IF NOT EXISTS PARTITION (age=18);

-- After adding a new partition to the table
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
|   age=18|
+---------+

-- Drop a partition from the table 
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
|   age=18|
+---------+

ALTER TABLE StudentInfo DROP IF EXISTS PARTITION (age=18);

-- After dropping the partition of the table
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
+---------+

-- Adding multiple partitions to the table
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
+---------+

ALTER TABLE StudentInfo ADD IF NOT EXISTS PARTITION (age=18) PARTITION (age=20);

-- After adding multiple partitions to the table
SHOW PARTITIONS StudentInfo;
+---------+
|partition|
+---------+
|   age=11|
|   age=12|
|   age=15|
|   age=18|
|   age=20|
+---------+

-- CLUSTER BY
DESC Teacher;
+------------------------+---------+-------+
|                col_name|data_type|comment|
+------------------------+---------+-------+
|                    name|   string|   NULL|
|                  gender|   string|   NULL|
|                 country|   string|   NULL|
|                     age|      int|   NULL|
|# Clustering Information|         |       |
|              # col_name|data_type|comment|
|                  gender|   string|   NULL|
+------------------------+---------+-------+

ALTER TABLE Teacher CLUSTER BY (gender, country);

-- After changing clustering columns
DESC Teacher;
+------------------------+---------+-------+
|                col_name|data_type|comment|
+------------------------+---------+-------+
|                    name|   string|   NULL|
|                  gender|   string|   NULL|
|                 country|   string|   NULL|
|                     age|      int|   NULL|
|# Clustering Information|         |       |
|              # col_name|data_type|comment|
|                  gender|   string|   NULL|
|                 country|   string|   NULL|
+------------------------+---------+-------+

ALTER TABLE Teacher CLUSTER BY NONE;

-- After removing clustering columns
DESC Teacher;
+------------------------+---------+-------+
|                col_name|data_type|comment|
+------------------------+---------+-------+
|                    name|   string|   NULL|
|                  gender|   string|   NULL|
|                 country|   string|   NULL|
|                     age|      int|   NULL|
|# Clustering Information|         |       |
+------------------------+---------+-------+

-- Change the fileformat
ALTER TABLE loc_orc SET fileformat orc;

ALTER TABLE p1 partition (month=2, day=2) SET fileformat parquet;

-- Change the file Location
ALTER TABLE dbx.tab1 PARTITION (a='1', b='2') SET LOCATION '/path/to/part/ways';

-- SET SERDE/ SERDE Properties
ALTER TABLE test_tab SET SERDE 'org.apache.hadoop.hive.serde2.columnar.LazyBinaryColumnarSerDe';

ALTER TABLE dbx.tab1 SET SERDE 'org.apache.hadoop' WITH SERDEPROPERTIES ('k' = 'v', 'kay' = 'vee');

-- SET TABLE PROPERTIES
ALTER TABLE dbx.tab1 SET TBLPROPERTIES ('winner' = 'loser');

-- SET TABLE COMMENT Using SET PROPERTIES
ALTER TABLE dbx.tab1 SET TBLPROPERTIES ('comment' = 'A table comment.');

-- Alter TABLE COMMENT Using SET PROPERTIES
ALTER TABLE dbx.tab1 SET TBLPROPERTIES ('comment' = 'This is a new comment.');

-- DROP TABLE PROPERTIES
ALTER TABLE dbx.tab1 UNSET TBLPROPERTIES ('winner');

-- RECOVER PARTITIONS
ALTER TABLE dbx.tab1 RECOVER PARTITIONS;
```

### Related Statements

* [CREATE TABLE](sql-ref-syntax-ddl-create-table.html)
* [DROP TABLE](sql-ref-syntax-ddl-drop-table.html)