擅长:python、mysql、java
<p>查询返回一堆行。包含单个值的行与仅包含该值的行不同(例如<code>1 != [1]</code>),因此需要从中提取单个字段:</p>
<pre><code>cursor3.execute('SELECT ... LIMIT 1', {'userid': userid})
total = cursor3.fetchone()[0]
</code></pre>
<p>或:</p>
<pre><code>cursor3.execute('SELECT ... LIMIT 1', {'userid': userid})
(total,) = cursor3.fetchone()
# total, = cursor3.fetchone() also works but it always looks funny to me
</code></pre>
<p>以上格式适用于具有多列的结果:</p>
<pre><code>cursor3.execute('SELECT a, b ... LIMIT 1', {'userid': userid})
total1, total2 = cursor3.fetchone()
</code></pre>