php - 如何根据另一表列从一个表中选择一列？

Question

我有 2 个表“用户”和“标准”。

用户

------------------------------
username, age, height, country
------------------------------

标准

-----------------------------------------------------------
username, age_from, age_to, height_from, height_to, country
-----------------------------------------------------------

我想写一个查询'用户'年龄在'age_from'和'age_to'之间

和

'height_from' 和 'height_to' 之间的 'users' 'height'

Answer 1

JOIN两张表：

SELECT  u.*
FROM Users          AS u
INNER JOIN criteria AS c  ON u.hiehgt BETWEEN c.height_from 
                                          AND c.height_to
                         AND u.age    BETWEEN c.age_from 
                                          AND c.age_to;

您可能还需要使用OUTER JOIN而不是INNER JOIN获取那些不匹配的行，请参阅此以获取更多信息：

• SQL 连接的可视化解释。

Answer 2

尝试：

SELECT u.* 
FROM users u
INNER JOIN criteria c
WHERE u.age    BETWEEN c.age_from AND c.age_to 
  AND u.height BETWEEN c.height_from AND c.height_to;