30 lines
1.2 KiB
Plaintext
30 lines
1.2 KiB
Plaintext
use test;
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drop table if exists tc1;
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create table tc1(c1 int not null primary key, c2 varchar(11));
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insert into tc1 values (1, 'aaa');
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insert into tc1 values (2, 'bbbb');
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insert into tc1 values (3, 'ccccc');
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create index idxc2 on tc1(c2);
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alter table tc1 add index idxc3(c1,c2);
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select * from tc1;
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c1 c2
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1 aaa
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2 bbbb
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3 ccccc
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show index from tc1;
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Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Visible Expression
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tc1 0 PRIMARY 1 c1 A NULL NULL NULL BTREE available YES NULL
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tc1 1 idxc2 1 c2 A NULL NULL NULL YES BTREE available YES NULL
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tc1 1 idxc3 1 c1 A NULL NULL NULL BTREE available YES NULL
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tc1 1 idxc3 2 c2 A NULL NULL NULL YES BTREE available YES NULL
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truncate table tc1;
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select * from tc1;
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c1 c2
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show index from tc1;
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Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Visible Expression
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tc1 0 PRIMARY 1 c1 A NULL NULL NULL BTREE available YES NULL
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tc1 1 idxc2 1 c2 A NULL NULL NULL YES BTREE available YES NULL
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tc1 1 idxc3 1 c1 A NULL NULL NULL BTREE available YES NULL
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tc1 1 idxc3 2 c2 A NULL NULL NULL YES BTREE available YES NULL
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drop table tc1;
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