SET @@session.storage_engine = 'MyISAM';
drop table if exists t1;
# Case 1. Partitioning by RANGE based on a non-stored virtual column.
CREATE TABLE t1 (
a DATE NOT NULL,
b int as (year(a))
)
PARTITION BY RANGE( b ) (
PARTITION p0 VALUES LESS THAN (2006),
PARTITION p2 VALUES LESS THAN (2008)
);
insert into t1 values ('2006-01-01',default);
insert into t1 values ('2007-01-01',default);
insert into t1 values ('2005-01-01',default);
select * from t1;
a	b
2005-01-01	2005
2006-01-01	2006
2007-01-01	2007
select partition_name,table_rows,data_length from information_schema.partitions where table_name = 't1';
partition_name	table_rows	data_length
p0	1	7
p2	2	14
# Modify the expression of virtual column b
ALTER TABLE t1 modify b int as (year(a)-1);
select * from t1;
a	b
2005-01-01	2004
2006-01-01	2005
2007-01-01	2006
select partition_name,table_rows,data_length from information_schema.partitions where table_name = 't1';
partition_name	table_rows	data_length
p0	2	14
p2	1	7
drop table t1;
# Case 2. Partitioning by LIST based on a stored virtual column.
CREATE TABLE t1 (a int, b int as (a % 3 ) persistent)
PARTITION BY LIST (a+1)
(PARTITION p1 VALUES IN (1), PARTITION p2 VALUES IN (2));
insert into t1 values (1,default);
select partition_name,table_rows,data_length from information_schema.partitions where table_name = 't1';
partition_name	table_rows	data_length
p1	0	0
p2	1	9
select * from t1;
a	b
1	1
select * from t1;
a	b
1	1
drop table t1;
# Case 3. Partitioning by HASH based on a non-stored virtual column.
CREATE TABLE t1 (
a DATE NOT NULL,
b int as (year(a))
)
PARTITION BY HASH( b % 3 ) PARTITIONS 3;
insert into t1 values ('2005-01-01',default);
insert into t1 values ('2006-01-01',default);
select * from t1;
a	b
2005-01-01	2005
2006-01-01	2006
select partition_name,table_rows,data_length from information_schema.partitions where table_name = 't1';
partition_name	table_rows	data_length
p0	0	0
p1	1	7
p2	1	7
# Modify the expression of virtual column b
ALTER TABLE t1 modify b int as (year(a)-1);
select * from t1;
a	b
2005-01-01	2004
2006-01-01	2005
select partition_name,table_rows,data_length from information_schema.partitions where table_name = 't1';
partition_name	table_rows	data_length
p0	1	7
p1	1	7
p2	0	0
drop table t1;
