如果想在已经建好的表上进行分区,如果使用alter添加分区的话,mysql会提示错误:
error 1505 <hy000> partition management on a not partitioned table is not possible
正确的方法是新建一个具有分区的表,结构一致,然后用insert into 分区表 select * from 原始表;
测试创建分区表文件
create table tr (id int, name varchar(50), purchased date)
partition by range(year(purchased))
(
partition p0 values less than (1990),
partition p1 values less than (1995),
partition p2 values less than (2000),
partition p3 values less than (2005)
);
插入测试数据
insert into tr values
(1, 'desk organiser', '2003-10-15′),
(2, 'cd player', '1993-11-05′),
(3, 'tv set', '1996-03-10′),
(4, 'bookcase', '1982-01-10′),
(5, 'exercise bike', '2004-05-09′),
(6, 'sofa', '1987-06-05′),
(7, 'popcorn maker', '2001-11-22′),
(8, 'aquarium', '1992-08-04′),
(9, 'study desk', '1984-09-16′),
(10, 'lava lamp', '1998-12-25′);
查询p2中的数据
select * from tr where purchased between '1995-01-01′ and '2004-12-31′;
如果删除p2,在删除p2分区的同时,也会将其下的所有数据删除
alter table tr drop partition p2;
show create table tr;
create table `tr` (
`id` int(11) default null,
`name` varchar(50) default null,
`purchased` date default null
) engine=myisam default charset=utf8
/*!50100 partition by range (year(purchased))
(partition p0 values less than (1990) engine = myisam,
partition p1 values less than (1995) engine = myisam,
partition p3 values less than (2005) engine = myisam) */
再次插入数据时,会将原p2的数据插入至p3中
insert into tr values (11, 'pencil holder', '1995-07-12′);
alter table tr drop partition p3;
select * from tr where purchased between '1995-01-01′ and '2004-12-31′;
创建一个新的测试表
create table members (
id int,
fname varchar(25),
lname varchar(25),
dob date
)
partition by range(year(dob)) (
partition p0 values less than (1970),
partition p1 values less than (1980),
partition p2 values less than (1990)
);
直接用alter table tablename add partition 方式再最后面添加分区
alter table members add partition (partition p3 values less than (2000));
alter table members reorganize partition p0 into (
partition m0 values less than (1960),
partition m1 values less than (1970)
);
show create table members;
create table `members` (
`id` int(11) default null,
`fname` varchar(25) default null,
`lname` varchar(25) default null,
`dob` date default null
) engine=myisam default charset=utf8
/*!50100 partition by range (year(dob))
(partition m0 values less than (1960) engine = myisam,
partition m1 values less than (1970) engine = myisam,
partition p1 values less than (1980) engine = myisam,
partition p2 values less than (1990) engine = myisam,
partition p3 values less than (2000) engine = myisam) */
使用 reorganize partition进行数据的合并与拆分,数据是没有丢失的。
(详细出处参考:)
如果用此方式在之前添加会报错,只能用另一种合并拆分分区的方式操作。
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