Question

我在数据库中有这些表：

country:

id      country
------------------
1       USA
2       Brazil

和细分表：

id      country
------------------
1       USA
2       Brazil

我有第三张表：

Id segment_id country_id

其中segment_id是段表

中id的外键

和country_id是国家/地区表中id的外键

myquestion是：

如何从具有3个表的内连接的其他表中进行选择，

我需要显示国家/地区的名称加上每个国家/地区在下拉菜单中显示所有细分如果有人可以帮助我

谢谢你

Answer 1

你只是试试这个

$sql = select * from third_table 
       inner join country on third_table.country_id = country.id
       inner join segment on third_table.segment_id = segment.id
$res = mysql_query($sql);

   'or'


   select * from TableA A 
   inner join TableB B on A.Column=B.Column 
   inner join TableC C on A.Column=C.Column

Answer 2

SELECT * 
FROM third_table t
INNER JOIN country c ON t.country_id = c.country_id
INNER JOIN segment s ON t.segment_id = s.segment_id

Answer 3

尝试此查询..这将有助于您创建列表

select countrysegments.id as countrysegmentsID, country.country as countryName,
segment.country as segmentName
from countrysegments 
       inner join country on countrysegments.country_id  = country.id
       inner join segment on countrysegments.segment_id = segment.id

3个表之间的内部联接

3 个答案: