连接类型：system > const > eq_ref > ref > range > index > ALL 依次减慢

1.

![image-20220527140947791](sql优化.assets/image-20220527140947791.png)

![image-20220527143134999](sql优化.assets/image-20220527143134999.png)

![image-20220527150123720](sql优化.assets/image-20220527150123720.png)

修改sql语句将 同意标识 !=1 改成 =0

![image-20220527153646669](sql优化.assets/image-20220527153646669.png)

![image-20220527161411940](sql优化.assets/image-20220527161411940.png)



2.

![image-20220527154421973](sql优化.assets/image-20220527154421973.png)

![image-20220527155232659](sql优化.assets/image-20220527155232659.png)

![image-20220527161715912](sql优化.assets/image-20220527161715912.png)

![image-20220527162139925](sql优化.assets/image-20220527162139925.png)

![image-20220527163054326](sql优化.assets/image-20220527163054326.png)![image-20220527163334845](sql优化.assets/image-20220527163334845.png)



3.

![image-20220527163728205](sql优化.assets/image-20220527163728205.png)![image-20220527164026570](sql优化.assets/image-20220527164026570.png)

![image-20220527174834556](sql优化.assets/image-20220527174834556.png)



4.

![image-20220528105518064](sql优化.assets/image-20220528105518064.png)

![image-20220528110539770](sql优化.assets/image-20220528110539770.png)



![image-20220528110817557](sql优化.assets/image-20220528110817557.png)



5.

![image-20220528110940645](sql优化.assets/image-20220528110940645.png)



![image-20220528141628305](sql优化.assets/image-20220528141628305.png)![image-20220528142021398](sql优化.assets/image-20220528142021398.png)



6.

![image-20220528142101511](sql优化.assets/image-20220528142101511.png)![image-20220528142707892](sql优化.assets/image-20220528142707892.png)

![image-20220528142934991](sql优化.assets/image-20220528142934991.png)



7.

![image-20220528143409890](sql优化.assets/image-20220528143409890.png)

![image-20220528144047536](sql优化.assets/image-20220528144047536.png)

![image-20220528144438531](sql优化.assets/image-20220528144438531.png)



8.

![image-20220528144515434](sql优化.assets/image-20220528144515434.png)![image-20220528144914701](sql优化.assets/image-20220528144914701.png)

![image-20220528145031910](sql优化.assets/image-20220528145031910.png)