Mysql索引优化

select * from payment where staff_id = 2 and customer_id = 584;

Mysql> select count(distinct customer_id),count(distinct staff_id) from payment;
+-----------------------------+--------------------------+
| count(distinct customer_id) | count(distinct staff_id) |
+-----------------------------+--------------------------+
|                         599 |                        2 |
+-----------------------------+--------------------------+

大专栏  Mysql索引优化lass="line">create table test(
id int not null primary key,//主键
name varchar(10) not null,
unique(id)//唯一索引
)engine = innodb;

create table test(
id int not null primary key,//主键
name varchar(10) not null,
key(name,id)//索引
)engine = innodb;

use information_schema;
select a.table_schema as '数据名',a.table_name as '表名',a.index_name as '索引1',b.index_name as '索引2',a.column_name as '重复列名' from statistics a join statistics b on a.table_schema = b.table_schema and a.table_name = b.table_name and a.seq_in_index = b.seq_in_index and a.column_name = b.column_name where a.seq_in_index = 1 and a.index_name <> b.index_name;