擅长:python、mysql、java
<p>当查询返回<code>0</code>行时<code>fetchone</code>将返回<code>None</code>:</p>
<pre><code>usernameSql = """SELECT Username FROM Details WHERE Password = '%s'""" % (passwordAttempt) # Selecting username in database
cur.execute(usernameSql)
usernameSql = cur.fetchone()
# check if the query return at least one record
if usernameSql:
userFetched = usernameSql[0]
else:
# show a error or somthing
</code></pre>