Github user hyunsik commented on a diff in the pull request:
https://github.com/apache/tajo/pull/618#discussion_r33930493
--- Diff: tajo-docs/src/main/sphinx/sql_language/alter_table.rst ---
@@ -0,0 +1,99 @@
+************************
+ALTER TABLE Statement
+************************
+
+========================
+RENAME TABLE
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> RENAME TO <new_table_name>
+
+ For example:
+ ALTER TABLE table1 RENAME TO table2;
+
+This statement lets you change the name of a table to a different name.
+
+========================
+RENAME COLUMN
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> RENAME COLUMN <column_name> TO <new_column_name>
+
+ For example:
+ ALTER TABLE table1 RENAME COLUMN id TO id2;
+
+This statement will allow users to change a column's name.
+
+========================
+ADD COLUMN
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> ADD COLUMN <column_name> <data_type>
+
+ For example:
+ ALTER TABLE table1 ADD COLUMN id text;
+
+This statement lets you add new columns to the end of the existing column.
+
+========================
+SET PROPERTY
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> SET PROPERTY (<key> = <value>, ...)
+
+ For example:
+ ALTER TABLE table1 SET PROPERTY 'timezone' = 'GMT-7'
+ ALTER TABLE table1 SET PROPERTY 'text.delimiter' = '&'
+ ALTER TABLE table1 SET PROPERTY
'compression.type'='RECORD','compression.codec'='org.apache.hadoop.io.compress.SnappyCodec'
+
+
+This statement will allow users to change a table's properties.
+
+========================
+ADD PARTITION
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> [IF NOT EXISTS] ADD PARTITION (<partition
column> = <partition value>, ...) [LOCATION = <partition's path>]
+
+ For example:
+ ALTER TABLE table1 ADD PARTITION (col1 = 1 , col2 = 2)
+ ALTER TABLE table1 ADD PARTITION (col1 = 1 , col2 = 2) LOCATION
'hdfs://xxx.com/warehouse/table1/col1=1/col2=2'
+
+You can use ``ALTER TABLE ADD PARTITION`` to add partitions to a table.
The location must be a directory inside of which data files reside. If the
location doesn't exist on the file system, Tajo will make the location by
force. ``ADD PARTITION`` changes the table metadata, but does not load data. If
the data does not exist in the partition's location, queries will not return
any results.
+
+========================
+ DROP PARTITION
+========================
+
+*Synopsis*
+
+.. code-block:: sql
+
+ ALTER TABLE <table_name> [IF NOT EXISTS] DROP PARTITION (<partition
column> = <partition value>, ...) [PURGE]
+
+ For example:
+ ALTER TABLE table1 DROP PARTITION (col1 = 1 , col2 = 2)
+ ALTER TABLE table1 DROP PARTITION (col1 = '2015' , col2 = '01', col3 =
'11' )
+ ALTER TABLE table1 DROP PARTITION (col1 = 'TAJO' ) PURGE
+
+You can use ``ALTER TABLE DROP PARTITION`` to drop a partition for a
table. This removes the data for a managed table and this doesn't remove the
data for an external table. But if ``PURGE`` is specified for an external
table, the partition data will be removed. For the reference, the metadata is
completely lost in all cases.
--- End diff --
the expression 'for the reference' seems to be not usual in English. Please
check it.
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