Question

我需要获得前3个推荐人以及他的推荐人数，但只有合格人员（表2）。我希望这是有道理的。到目前为止，我有以下查询。请帮忙。谢谢

SELECT count(*) as total_referrals, referrer
FROM table_1
WHERE table_2.qualified = '1'
GROUP BY referrer
ORDER BY total_referrals DESC 
LIMIT 0,3

TABLE_1

referrer   referral
user1      user89
user1      user54
user1      user23
user1      user56
user2      user89
user2      user23
user2      user45
user3      user78
user3      user14
user4      user10
user5      user98
user5      user56
...

TABLE_2

referral   qualified
user89       1
user54       0
user23       0
user56       1
user89       1
user23       1
user45       0
user78       1
user14       1
user10       0
user98       1
user56       1
...

Answer 1

您需要引用from子句中的两个表，并确定您的字段名称是引用者还是用户名：

SELECT count(table_1.referrals) as total_referrals, referrer
FROM table_1 left join table_2 on table_1.referrals=table_2.referrals
WHERE table_2.qualified = '1'
GROUP BY table_1.referrer
ORDER BY total_referrals DESC 
LIMIT 0,3

Answer 2

更新2

http://sqlfiddle.com/#!9/2f598/5

以下查询似乎可以完成这项工作：

SELECT aa.referrer, COUNT(*) AS total_referrals
FROM table_1 AS aa
INNER JOIN (
    SELECT referral
    FROM table_2
    WHERE qualified = 1
    GROUP BY referral
) AS _bb
ON aa.referral = _bb.referral
GROUP BY aa.referrer
ORDER BY total_referrals DESC
LIMIT 3;

从2个表中获取具有条件的行

2 个答案: