如果單元格中存在字符串，則更新單元格內容MySQL

Question

我有一個包含很多行（大約1,500）的表格。在city_name列中，一些單元格具有城市名稱並以（CD）結尾。我希望帶有（CD）的單元在沒有（CD）的情況下更新。這是我的表的預覽：

+---------+-----------------------+---------+ 
| city_id | city_name    | id_dept | 
+---------+-----------------------+---------+ 
|  1 | El Encanto (CD)  |  1 | 
|  2 | La Chorrera (CD)  |  1 | 
|  3 | La Pedrera (CD)  |  1 | 
|  4 | La Victoria (CD)  |  1 | 
|  5 | Leticia    |  1 | 
|  6 | Miriti Parana (CD) |  1 | 
|  7 | Puerto Alegria (CD) |  1 | 
|  8 | Puerto Arica (CD)  |  1 | 
|  9 | Puerto Nariño   |  1 | 
|  10 | Puerto Santander (CD) |  1 | 
+---------+-----------------------+---------+ 
10 rows in set (0.00 sec) 

而這正是我想有：

+---------+-----------------------+---------+ 
| city_id | city_name    | id_dept | 
+---------+-----------------------+---------+ 
|  1 | El Encanto   |  1 | 
|  2 | La Chorrera   |  1 | 
|  3 | La Pedrera   |  1 | 
|  4 | La Victoria   |  1 | 
|  5 | Leticia    |  1 | 
|  6 | Miriti Parana   |  1 | 
|  7 | Puerto Alegria  |  1 | 
|  8 | Puerto Arica   |  1 | 
|  9 | Puerto Nariño   |  1 | 
|  10 | Puerto Santander  |  1 | 
+---------+-----------------------+---------+ 
10 rows in set (0.00 sec) 

嗯，我明白我可以使用選擇所有（CD）的行：

SELECT * FROM city WHERE city_name LIKE ("%(CD)%") 

但我怎麼刪除（CD）：

UPDATE city SET city_name = "" WHERE city_name LIKE("%(CD)%") 

Answer 1

您可以使用REPLACE()功能

UPDATE city SET city_name = REPLACE(city_name, '(CD)', '') 
WHERE city_name LIKE("%(CD)%") 

Answer 2

如果它總是以「（CD）」結束，要砍那些關底，你可以這樣做：

UPDATE city 
SET city_name = LEFT(city_name, CHAR_LENGTH(city_name) - 5) 
WHERE city_name LIKE '% (CD)';