如何根据另一个表列从一个表中选择一列？

Question

I have 2 tables 'users' and 'criteria'.

users

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

criteria

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

I want to write a query that 'users' age between 'age_from' and 'age_to'

AND

'users' 'height' between 'height_from' and 'height_to'

Answer 1

JOIN the two tables:

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;

You might also need to use OUTER JOIN instead of INNER JOIN to get those unmatched rows, see this for more information:

• A Visual Explanation of SQL Joins.