將這兩個SQL語句合併爲一個

Question

將這兩個SQL語句合併爲一個的最佳方式是什麼？我嘗試過使用聯盟，但似乎無處可去。

select id as id from likes where type=1; 

select sum(votes) as votes from likes where parent=id; 

這裏是likes表：

id type parent country votes 
1  1  0  US  0 
2  2  1  US  6 // This + 
19  3  1  US  3 // This 
3  3  2  US  3 
7  3  2  US  3 
4 10  3  US  1 
5 10  3  US  1 
6 10  3  US  1 
10 10  7  US  1 
9 10  7  US  1 
8 10  7  US  1 
20 10  19  US  1 
21 10  19  US  1 
22 10  19  US  1 

這是我想要達到的效果：

id | votes 
--------------- 
1 | 9 

Answer 1

試試這個：

SELECT 
    l1.id, 
    SUM(l2.votes) AS Totalvotes 
FROM likes AS l1 
INNER JOIN likes AS l2 ON l1.id = l2.parent 
WHERE l1.type = 1 
GROUP BY l1.id; 

看到它在此採取行動：

• SQL Fiddle Demo

這會給你：

| ID | TOTALVOTES | 
------------------- 
| 1 |   9 | 

Answer 2

SELECT SUM(votes) AS votes 
FROM likes 
WHERE parent IN (SELECT id FROM likes WHERE type=1) 

HTH

Answer 3

你可以試試這個

select id,sum(votes) as votes from likes where type=1 and parent=id; 

希望這有助於

Answer 4

這應該解決您的問題，我相信：

SELECT parent AS id, SUM(votes) AS votes FROM likes WHERE parent IN (SELECT id FROM likes WHERE type = 1) GROUP BY parent;