oceanbase

1
use test;
2
drop table if exists tc1;
3
create table tc1(c1 int not null primary key, c2 varchar(11));
4
insert into tc1 values (1, 'aaa');
5
insert into tc1 values (2, 'bbbb');
6
insert into tc1 values (3, 'ccccc');
7
create index idxc2 on tc1(c2);
8
alter table tc1 add index idxc3(c1,c2);
9
select * from tc1;
10
c1	c2
11
1	aaa
12
2	bbbb
13
3	ccccc
14
show index from tc1;
15
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment	Visible	Expression
16
tc1	0	PRIMARY	1	c1	A	NULL	NULL	NULL		BTREE	available		YES	NULL
17
tc1	1	idxc2	1	c2	A	NULL	NULL	NULL	YES	BTREE	available		YES	NULL
18
tc1	1	idxc3	1	c1	A	NULL	NULL	NULL		BTREE	available		YES	NULL
19
tc1	1	idxc3	2	c2	A	NULL	NULL	NULL	YES	BTREE	available		YES	NULL
20
truncate table tc1;
21
select * from tc1;
22
c1	c2
23
show index from tc1;
24
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment	Visible	Expression
25
tc1	0	PRIMARY	1	c1	A	NULL	NULL	NULL		BTREE	available		YES	NULL
26
tc1	1	idxc2	1	c2	A	NULL	NULL	NULL	YES	BTREE	available		YES	NULL
27
tc1	1	idxc3	1	c1	A	NULL	NULL	NULL		BTREE	available		YES	NULL
28
tc1	1	idxc3	2	c2	A	NULL	NULL	NULL	YES	BTREE	available		YES	NULL
29
drop table tc1;
30