我想從2個不同的表中提取數據

Question

我想獲取引起master.category如果我有

$category ='doctor' 

明智假設那我怎麼才能得到結果？我已經繪製了下面的表格和預期的結果，請幫助我。感謝

table name->Master 
------------------ 

id  label  category 

1  expertise  doctor 
2   fee   doctor 
3  appontment  doctor 
4  services  lawyer 
5  qualification student 





table name->Field 
------------------ 

id  label_id  Information 
1   1   desntist 
2   1   general_physician 
3   1   general_surgeons 
4   4   criminal_law 
5   5   civil_law 



expected result    
-------------------- 
expertise  

dentist 
general_physician 
general_surgeons 

Answer 1

執行JOIN像

select f.information as 'expertise' 
from field f 
join master m on m.id = f.label_id 
where m.category = 'doctor'; 

Answer 2

其查詢得到的所有信息通過大師的ID

SELECT m.label, GROUP_CONCAT(Information) 
FROM Master m 
JOIN Field f 
ON m.id = f.label_id 
WHERE m.category = 'doctor'