mysql - 3 个表中的左外连接

Question

我有 3 张 table
车间和业主
shop是父表，另外2个是子表

SHOP    
s_id, floor_id,s_owner,s_remarks
1,2,1,big shop   
2,2,3,near bank   
3,1,2,corner   
4,7,7,FAKE FLOOR AND OWNER   

OWNERS   
o_id, o_name, contact
1,gale,009659999999   
2,smith,00447676767   
3,pathan,0088787878   

FLOORS   
f_id, f_name
1,FIRST FLOOR   
2,SECOND FLOOR  
3,THIRD FLOOR   


select shop.s_id, floors.f_name, owners.o_id, s_remarks  
from ? join ? 

即使业主或楼层没有相关记录，也可显示店铺的所有记录

Answer 1

正如您在标题中所建议的，您需要使用LEFT JOIN。这应该可以帮助您开始:

SELECT shop.s_id, floors.f_name, owners.o_id, s_remarks
FROM ?
LEFT JOIN ? ON ? = ?
LEFT JOIN ? ON ? = ?

您只需将问号替换为正确的表或列名称。