有条件的左联接中的查询问题

Question

我有这个查询，可以帮助我获取当前用户的积分，现在，我在设置条件时遇到问题...

$query4 =  'SELECT u.*, SUM(c.ts) AS total_sum1, SUM(r.bv) AS total_sum 
FROM users u 
LEFT JOIN 
 (SELECT user_id ,SUM(points) AS ts FROM coupon GROUP BY user_id) c 
 ON u.user_id=c.user_id AND u.user_id="'.$_SESSION['user_name'].'"
LEFT JOIN 
 (SELECT user_id ,SUM(basket_value) AS bv FROM retailer GROUP BY user_id) r 
ON u.user_id=r.user_id 
GROUP BY u.user_id';

我的问题是AND u.user_id="'.$_SESSION['user_name'].'"

我需要为该特定用户找到要点。.我做错了吗？ 我的意思是，我知道我是，但是呢？ 谢谢

Answer 1

这样写你的查询

$query4 =  'SELECT u.*, SUM(c.ts) AS total_sum1, SUM(r.bv) AS total_sum 
FROM users u 
LEFT JOIN 
 (SELECT user_id ,SUM(points) AS ts FROM coupon GROUP BY user_id) c 
 ON u.user_id=c.user_id 
LEFT JOIN 
 (SELECT user_id ,SUM(basket_value) AS bv FROM retailer GROUP BY user_id) r 
ON u.user_id=r.user_id 
where u.user_id="'.$_SESSION['user_name'].'"
GROUP BY u.user_id';