擅长:python、mysql、java
<p>试试这样的方法:</p>
<pre><code>SELECT *
FROM validity_period
WHERE valid_from <= current_date
AND valid_to >=current_date
UNION
--Gets the last instance where valid_until is null
SELECT *
FROM validity_period
WHERE valid_from <= current_date
AND valid_to IS NULL
ORDER BY id DESC LIMIT 1
</code></pre>
<p>如果需要第一个而不是最后一个空字段,只需删除DESC</p>