本帖最后由 sstutu 于 2014-7-8 23:20 编辑
问题导读:
本文包含了基本操作:
1.如何添加、删除分区?
2.如何修改分区操作?
3.如何添加、修改列?
添加分区
- ALTER TABLE table_name ADD PARTITION (partCol = 'value1') location 'loc1'; //示例
- ALTER TABLE table_name ADD IF NOT EXISTS PARTITION (dt='20130101') LOCATION '/user/hadoop/warehouse/table_name/dt=20130101'; //一次添加一个分区
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- ALTER TABLE page_view ADD PARTITION (dt='2008-08-08', country='us') location '/path/to/us/part080808' PARTITION (dt='2008-08-09', country='us') location '/path/to/us/part080809'; //一次添加多个分区
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删除分区
- ALTER TABLE login DROP IF EXISTS PARTITION (dt='2008-08-08');
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- ALTER TABLE page_view DROP IF EXISTS PARTITION (dt='2008-08-08', country='us');
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修改分区
- ALTER TABLE table_name PARTITION (dt='2008-08-08') SET LOCATION "new location";
- ALTER TABLE table_name PARTITION (dt='2008-08-08') RENAME TO PARTITION (dt='20080808');
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添加列
- ALTER TABLE table_name ADD COLUMNS (col_name STRING); //在所有存在的列后面,但是在分区列之前添加一列
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修改列
- CREATE TABLE test_change (a int, b int, c int);
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- // will change column a's name to a1
- ALTER TABLE test_change CHANGE a a1 INT;
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- // will change column a's name to a1, a's data type to string, and put it after column b. The new table's structure is: b int, a1 string, c int
- ALTER TABLE test_change CHANGE a a1 STRING AFTER b;
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- // will change column b's name to b1, and put it as the first column. The new table's structure is: b1 int, a string, c int
- ALTER TABLE test_change CHANGE b b1 INT FIRST;
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修改表属性:
- alter table table_name set TBLPROPERTIES ('EXTERNAL'='TRUE'); //内部表转外部表
- alter table table_name set TBLPROPERTIES ('EXTERNAL'='FALSE'); //外部表转内部表
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表的重命名
- ALTER TABLE table_name RENAME TO new_table_name
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