关于连接的mySQL更新查询

Question

我有一个国家数据库和另一个名为区域的表.

Countries 
[id, name, status (1 enabled 0 disabled) ]


Zones 
[id, name, country_id]

我使用以下查询来匹配所有国家/地区的区域.

select 
z.name as state, 
z.id as state_id, 
c.name as country_name, 
c.id as country_id, 
c.status as country_status 
from countries c left join zones z on c.id = z.country_id 

所以基本上简而言之,区域是状态,输出就是这样.

+-----------------------------------------------------+----------+---   -----------------------------------------+------------+----------------+
| state                                               | state_id | country_name                               | country_id | country_status     |
+-----------------------------------------------------+----------+---  -----------------------------------------+------------+----------------+
| NULL                                                |     NULL | Christmas Island                           |         45 |              1   
| NULL                                                |     NULL | Puerto Rico                                |        172 |              1    
| NULL                                                |     NULL   Isle of Man                                |        254 |              1  
| Álava                                        |     2971 | Spain                                      |        195 |              1   
| Ávila                                        |     2976 | Spain                                      |        195 |              1 
| Évora                                        |     2656 | Portugal                                   |        171 |              1   

输出很大,粘贴在这里,所以只显示在结果的末尾

我想将国家/地区的状态更新为0,其中没有区域.知道我怎么能通过mySQL做到这一点？

Answer 1

你可以not in像这样使用:

 update Countries set status=0 where id not in (select distinct country_id from Zones )