我有三张桌子.
地点
ID | NAME | TYPE |
1 | add1 | stat |
2 | add2 | coun |
3 | add3 | coun |
4 | add4 | coun |
5 | add5 | stat |
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学校
ID | NAME
1 | sch1
2 | sch2
3 |sch3
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school_locations
ID |LOCATIONS_ID |SCHOOL_ID
1 | 1 |1
2 | 2 |2
3 | 3 |3
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这里的表位置包含应用程序的所有位置.学校的位置由ID调用.
当我使用查询
select locations.name from locations where type="coun";
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它显示类型为"coun"的名称
但是我想显示locations.name,其中只有school_locations有type ="coun"
我尝试了以下查询,但似乎都没有工作
select locations.name
from locations
where type="coun"
inner join school_locations
on locations.id=school_locations.location_id
inner join schools
on school_locations.school.id=schools.id;
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和
select locations.name
from locations
inner join school_locations
on locations.id=school_locations.location_id
inner join schools
on school_locations.school.id=schools.id where type="coun";
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是否可以在查询中使用多个内部联接,还是有另一种方式?
kni*_*ttl 57
SELECT `locations`.`name`
FROM `locations`
INNER JOIN `school_locations`
ON `locations`.`id` = `school_locations`.`location_id`
INNER JOIN `schools`
ON `school_locations`.`school_id` = `schools_id`
WHERE `type` = 'coun';
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该WHERE
条款必须在声明的最后