1. Specify the initial value of the AUTO_INCREMENT self-increment (ie the starting value) when creating the table :
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1
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CREATE
TABLE
XXX (ID
INT
(5)
PRIMARY
KEY
AUTO_INCREMENT) AUTO_INCREMENT=100;
|
2. Modify the initial value through ALTER TABLE (but it must be greater than the AUTO_INCREMENT self-increment in the table, otherwise the setting will be invalid):
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1
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ALTER
TABLE
XXX AUTO_INCREMENT=100;
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3. If the maximum value of the auto-increment sequence is deleted, the value is reused when inserting a new record:
That is to say, if there are AUTO_INCREMENT attribute values in the table with consecutive values of 78 and 100, but the data of 100 has been deleted, when the data is added next, the auto-increment value is 101, and 100 is reused.
Even after you delete all data in the entire table, the previous maximum value of the auto-increment sequence will be reused.
The solution is:
Use ALTER TABLE XXX AUTO_INCREMENT=0; to reset the auto-increment initial value.
Set the AUTO_INCREMENT_INCREMENT and AUTO_INCREMENT_offset user variable values: (After restarting MySQL, these changes will revert to the initial value of 1)
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1
2
3
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SET
auto_increment_increment=10; #自增量每次增加的值改为10，
SET
auto_increment_offset=2; #第一次加载数值时的偏移值的个位值
SHOW VARIABLES
LIKE
'AUTO_INC%'
; #查看修改后变量的值
|
in addition:
mysql>SHOW TABLE STATUS FROM NAME_DB; -->Display information of all tables in database NAME_DB
mysql>SHOW CREATE TABLE NAME_TBL; -->Display information when table NAME_TBL was created
mysql>SHOW VARIABLES LIKE 'AUTO_INC%' --> Display MySQL's user session variables at the beginning of AUTO_INC (SHOW GLOBAL VARIABLES)
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| auto_increment_increment| 1 |
| auto_increment_offset | 1 |
+--------------------------+-------+
Change the names, attributes, etc. of the fields in the table:
mysql>ALTER TABLE XXX COL_NAME COL_NEW_NAME VARCHAR(20) [ELSE...]; #Rename the field COL_NAME in the table to COL_NEW_NAME