# Hotspot of Clustered Index

```
CREATE TABLE sbtest1(
 ~!@id int(11) NOT NULL AUTO_INCREMENT,@!~
 k int(11) NOT NULL DEFAULT '0',
 c char(120) NOT NULL DEFAULT '',
 pad CHAR(60) DEFAULT '' NOT NULL,
 ~!@PRIMARY KEY (id) CLUSTERED@!~
)
CREATE TABLE sbtest2(
 ~!@id int(11) NOT NULL,@!~
 k int(11) NOT NULL DEFAULT '0',
 c char(120) NOT NULL DEFAULT '',
 pad CHAR(60) DEFAULT '' NOT NULL,
 ~!@PRIMARY KEY (id) CLUSTERED@!~
)
```
----------------------------------------------------
In general, there are two common ways to create a Clustered Index Table:
```
CREATE TABLE sbtest1(
 id int(11) NOT NULL AUTO_INCREMENT,
 k int(11) NOT NULL DEFAULT '0',
 c char(120) NOT NULL DEFAULT '',
 pad CHAR(60) DEFAULT '' NOT NULL,
 PRIMARY KEY (id) CLUSTERED
);

CREATE TABLE sbtest2(
 id int(11) NOT NULL,
 k int(11) NOT NULL DEFAULT '0',
 c char(120) NOT NULL DEFAULT '',
 pad CHAR(60) DEFAULT '' NOT NULL,
 PRIMARY KEY (id) CLUSTERED
);
```
For both sbtest1 and sbtest2, the keys after being transformed into key-value pairs are in the format of "Table ID_Primary Key." In the case of sbtest2, the id column is the primary key and has business properties, such as order number, phone number, or employee ID, which may not be continuous when inserting rows into the table. However, for sbtest1, the ID primary key column has the AUTO_INCREMENT attribute, causing the value of each row's ID primary key column to be incremented by 1 compared to the previous row every time a new row is inserted.