How to update index in mysql when a row is deleted

Question

really sorry if someone already asked this question, I couldn't find it and I'm stuck with it. So if I have three records in table car :

1 | Maserati | red

2 | Ferarri | red

3 | Audi | blue

...and I delete Ferarri record, I'm left with :

1 | Maserati | red
3 | Audi | blue

Is there a way to have this table automatically indexed as such :

1 | Maserati | red
2 | Audi | blue

Note: I have an index column which is set to autoincrement.

Thanks a lot!

Answer 1

时间（绝对不是在每次删除查询之后），您可以运行以下语句：

• CHECK TABLE tab; - 检查表是否有错误，MyISAM - 更新密钥统计信息！
• ANALYZE TABLE tab; - 执行密钥分发分析。
• OPTIMIZE TABLE tab; - 重新组织表数据和相关索引数据的物理存储（碎片整理）。

它们将提高您的索引性能。