MySQL优化常见Extra分析案例
摘要:数据准备: create table user ( id int primary key, name varchar(20), sex varchar(5), index(name) )engine=innodb; 数据说明:用户表:id主键索引,name普通索引(非唯一),sex无索引;四行记录:
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posted @ 2021-07-28 23:19
posted @ 2021-07-28 23:19
posted @ 2021-07-20 09:59
posted @ 2021-07-17 14:30