How to rearrange ids in mysql

Mysql method to rearrange ids: 1. Use column counting [alter table tablename drop column id]; 2. Use increment arrangement [alter table tablenam auto_increment].

Mysql's method of rearranging IDs:

When using mysql, there is usually an auto-increment in the table The id field, but when we want to clear the data in the table and re-add the data, we hope that the id will start counting from 1 again. We can use the following two methods:

Method 1:

alter table tablename drop column id;
alter table tablename add id mediumint(8) not null primary key auto_increment first;

Method 2:

alter table tablename auto_increment=0

Method 2 will not clear the existing data, and the operation is more flexible. It can not only reset the auto-increment value to zero, but is also suitable for resetting the auto-increment value and inserting new data after deleting a large number of consecutive rows. ; Or start from a new value, which of course cannot conflict with the existing value.

$sql="delete from $table_vote"; 
mysql_query($sql, $link); 
$sql="alter table $table_vote auto_increment=1"; 
mysql_query($sql, $link);

More related free learning recommendations: mysql tutorial(Video)

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