# 几何索引
Goods 数据库中有一个 shop 表,其中包含如下字段:
```mysql
create table shop (
id int primary key auto_increment,
location GEOMETRY
-- ...
)
```
现在 Joe 要给 location 字段加上几何索引,他应该怎么做?
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## 答案
```mysql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX geo_index(location);
```
## 选项
### A
```mysql
alter table shop add INDEX geo_index(location);
```
### B
```mysql
alter table shop add INDEX location;
```
### C
```mysql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX location;
```
### D
```mysql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX location;
```