Mysql索引-白红宇

Mysql索引

阅读量：93 次

发布时间：2019-02-25

本文共 1505 字，大约阅读时间需要 5 分钟。

MySQL?????????????

??????????????????????????????????????????????????????????????????????????????MySQL???

????????

???MySQL??????????????????????????????????????????????????????????????????????????????????MySQL??????????????????????????

???????

??????????????IO??????????????????????????????????????????????????B+??????????????????????????IO???

B+??????

B+????????????????????????????????????

???????????????????????????IO???

?????????????????????????????

?????????????????????

???????????????????????IO???????????????????????

B+????

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????????????????????int??????????????????????

??????????

B+???????????????????????????????????????????

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1. ????

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??????????????????????????

2. ??????

???????ID??????????????????

?????????????????????????

???????????????????????

?????????

1. ????

??????????

create table s1(  id int,  name varchar(20),  gender char(6),  email varchar(50),  primary key(id));

create index idx_name on s1(name);

???????
```
create index idx_id on s1(id);
```

?????
```
drop index idx_name on s1;
```

2. ??????

?????????????????????????

??????????????????????

??????????????????

?????????

???????????????????

??????email LIKE '%cn%'?

??????reverse(email) = 'wupeiqi'?

???????????nid != 123??nid???????????

???????

????????????????????

????*????????????

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????????????????????????????????????????IO???????????????????????????????????????????????????????????????????

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