php - 组合或交叉多个 MySQL 命令

Question

我必须搜索两个表。

我的第二个表是:

+---------+---------------+-------+
| user_id | is_first_time | score |
+---------+---------------+-------+
|   44    |       1       |   20  |
+---------+---------------+-------+
|   44    |       0       |   20  |
+---------+---------------+-------+

我的第一个表仅包含用户信息。

• 如果我使用以下 MySQL 命令，我将得到结果:

  SELECT * , users_score.user_id users_score_user_id 
  FROM users JOIN users_score 
  ON users_score.user_id = users.id 
  WHERE (users_score.score='20' AND users_score.is_first_time='1')
  

• 如果我使用以下 MySQL 命令，我也会得到结果(我只需将“is_first_time”值更改为“0”:

  SELECT * , users_score.user_id users_score_user_id 
  FROM users JOIN users_score 
  ON users_score.user_id = users.id 
  WHERE (users_score.score='20' AND users_score.is_first_time='0')
  

• 但是如果我将这两个命令与 AND 结合起来，我将不会得到任何结果:

  SELECT * , users_score.user_id users_score_user_id 
  FROM users JOIN users_score 
  ON users_score.user_id = users.id 
  WHERE (users_score.score='20' AND users_score.is_first_time='1')
  AND (users_score.score='20' AND users_score.is_first_time='0')
  

如何组合或交叉这两个命令？

感谢您的帮助。

Answer 1

您需要在此处使用OR条件

WHERE (users_score.score='20' AND users_score.is_first_time='1') 
  OR  (users_score.score='20' AND users_score.is_first_time='0')

但是可以使用 IN 条件以更好的方式编写

SELECT *,
       users_score.user_id users_score_user_id
FROM   users
       JOIN users_score
         ON users_score.user_id = users.id
WHERE  users_score.score = '20'
       AND users_score.is_first_time IN ( '1', '0' )