mysql - SQL 中的类别列

Question

我只是想知道这是否是使用类别的最有效方式:

---------------------------------
| ID   | ITEM      | CATEGORY   |
---------------------------------
| 1    | COOKIES   | FOOD       |
| 2    | CAKE      | FOOD       |
| 3    | WATER     | DRINK      |
| 4    | PEANUTS   | FOOD       |
| 5    | PEPSI     | DRINK      |
---------------------------------
 ↑ int  ↑ text      ↑ text        <- [ type of column ]

那么我的查询是:

SELECT * FROM `table` WHERE category='FOOD';

Answer 1

我想如果你稍微改变一下，例如类别 ID 中的类别列，

`---------------------------------
| ID   | ITEM      | CATEGORY   |
---------------------------------
| 1    | COOKIES   | 1          |
| 2    | CAKE      | 1          |
| 3    | WATER     | 2          |
| 4    | PEANUTS   | 1          |
| 5    | PEPSI     | 2          |

加上类别表

--------------------
| ID   | ITEM      | 
--------------------
| 1    | FOOD  
| 2    | DRINK     

AND 查询:

SELECT * FROM `table` WHERE category=1;   (or 2)