使用查詢獲取父＆子數據

Question

我有2個表。

（1）稅：父表

id title 
1 service tax 
2 vat 

（2）cess_taxes：子表

id tax_id title 
1  2 cess vat 
2  1 cess service 
3  1 add. service 

我想下面數據，

id title* 
1 service tax (parent) 
2 cess service (child) 
3 add. service (child) 
4 vat (parent) 
5 cess vat (child) 

如何使用查詢獲取數據？

我試圖與左，右&內加入

SELECT t.id, t.title, c.id, c.title 
FROM `taxes` AS t 
LEFT JOIN cess_taxes AS c ON c.tax_id = t.id 

Answer 1

SET @rn:=0; 
SELECT @rn:=@rn+1 AS rank, title,id 
FROM (
    SELECT title,id 
    FROM taxes 

    Union 

    SELECT c.title, 
     case when t.id=1 then 1.5 else 3 end 
    FROM cess_taxes c 
    inner join taxes t 
    on t.id=c.tax_id 


) t1 
Order By id 

SQL Fiddle Demo