即使在第二張表中找不到匹配項，也從第一張表中獲取結果-MySQL

Question

我有兩個表，其結構如下

Table name = counter
ref_id INT NOT NULL
count INT NOT NULL

---

Table name = favs
disqus_id VARCHAR(32) NOT NULL
user_id INT NOT NULL
dormant VAHCHAR(10) NOT NULL

我運行此查詢=> SELECT count, dormant FROM counter AS c LEFT JOIN favs AS f ON c.ref_id = f.disqus_id WHERE ref_id = 'post_5' AND user_id = '1'.

但是，如果在第二個表favs找不到匹配項，則不返回任何行。 我想要的是，如果找到結果，它應該返回兩個列，否則返回兩個列都為NULL

我該怎么做呢？

Answer 1

ON子句中用戶的條件

SELECT c.count, f.dormant 
FROM   counter AS c 
       LEFT JOIN favs AS f 
          ON c.ref_id = f.disqus_id  AND f.user_id = '1'
WHERE  c.ref_id = 'post_5' 

或者，如果仍然不起作用，請同時移動兩個：

SELECT c.count, f.dormant 
FROM   counter AS c 
       LEFT JOIN favs AS f 
          ON c.ref_id = f.disqus_id  AND 
             f.user_id = '1' AND
             c.ref_id = 'post_5'