就查询性能而言，SQL WHERE子句中整数的位比较实际上是免费的。

碰巧，对于前50万行左右来说，这在某种程度上是正确的。在那之后，它被证明是完全无联合国的。

In the early days, most personal computers had a cassette tape interface for loading and storing programs. I did not have a computer at this time but read everything I could get my hands on (mostly magazines) that had anything to do with computers (this was the late 70's - no internet for me). For some reason I was under the impression that programs were executed directly from the cassette tape and that the only reason computers had any RAM was to store variables while the program ran. I figured that when the code had to execute a jump instruction, it would somehow rewind or advance the tape to the correct position and continue from there.

这种编程是不可能的。

不是开玩笑的，我一直认为编程是一种不可能学会的东西，我总是远离它。当我接近代码的时候，我永远也无法理解它。

然后有一天，我坐下来阅读了一些基本的初学者教程，并从那里开始学习。现在我是一名程序员，我热爱工作的每一分钟。

另外，我认为编程并不容易，它是一个挑战，我更喜欢学习，没有什么比解决一些编程问题更有趣的了。

人们知道他们想要什么。

在很长一段时间里，我以为我会和人们交谈，他们会描述一个问题或工作流程，我将其放入代码并自动化。结果每次发生这种情况，他们以为自己想要的并不是他们真正想要的。

Edit: I agree with most of the comments. This is not a technical answer and may not be what the questioner was looking for. It doesn't apply only to programming. I'm sure it's not my longest-held assumption either, but it was the most striking thing I've learned in the 10 short years I've been doing this. I'm sure it was pure naivete on my part but the way my brain is/was wired and the teaching and experiences I had prior to entering the business world led me to believe that I would be doing what I answered; that I would be able to use code and computers to fix people's problems.

我想这个答案类似于Robin关于非程序员理解/关心我所谈论的内容的回答。这是关于将业务作为一个敏捷的、迭代的、交互的过程来学习。它是关于学习编程猴子和软件开发人员之间的区别。这是关于意识到两者之间的区别，并且在该领域真正优秀，不仅仅是语法和输入速度。

编辑:这个答案现在是社区-wiki，以安抚人们对这个答案感到不安，给我代表。

除了插入/冒泡排序之外，任何事情都是非常简单的黑魔法。

XML名称空间(或者更糟，格式良好)在某种程度上比没有它们要困难得多。

一个非常常见的错误，甚至在W3C!