IndexError：列表索引超出范围：Python

Question

我在浏览器上尝试使用我的python脚本但是我一直收到这个错误。我忽略了什么吗？

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追踪（最近一次呼叫最后一次）：

File "./index.py", line 50, in <module>
    cid = app.db.execute('select id from clients where status="active" order by id desc limit 1')[0][0]
IndexError: list index out of range