Oracle有几个SQL WTF问题。

Oracle将空字符串处理为null。 在“<>”比较中处理空值。 创建表WTF(键数为主键，动物varchar2(10)); 插入WTF值(1，'dog'); Insert into WTF values (2， "); Insert into WTF values (3，'cat'); Select * from WTF where animal <> 'cat';

唯一返回的行是(1，'dog')行。

在Matlab中，以下内容可能会让你感到惊讶，特别是如果你习惯了Python:

>> not true

ans =

     0     0     0     0
>> not false

ans =

     0     0     0     0     0

这里有两个奇怪的特征。第一个是a b被解释为a('b')，因此非真被解释为not('true')。第二个奇怪的特征是没有任何字符返回0(大概是因为在matlab中没有false或true，只有0或1)。

JavaScript日期全是WTF。

var d = new Date("1/1/2001");

var wtfyear = d.getYear(); // 101 (the year - 1900)
// to get the *actual* year, use d.getFullYear()

var wtfmonth = d.getMonth(); // 0
// months are 0-based!

在fortran中(当然是77，可能在95中也是如此)，未声明的变量和以I到N开头的参数(“In”组)将是INTEGER，所有其他未声明的变量和参数将是REAL(源)。这与“在某些情况下可选的空白”相结合，导致了最著名的错误之一。

正如弗雷德·韦伯在1990年的《另类民间传说:计算机》一书中所说:

I worked at Nasa during the summer of 1963. The group I was working in was doing preliminary work on the Mission Control Center computer systems and programs. My office mate had the job of testing out an orbit computation program which had been used during the Mercury flights. Running some test data with known answers through it, he was getting answers that were close, but not accurate enough. So, he started looking for numerical problems in the algorithm, checking to make sure his tests data was really correct, etc. After a couple of weeks with no results, he came across a DO statement, in the form: DO 10 I=1.10 This statement was interpreted by the compiler (correctly) as: DO10I = 1.10 The programmer had clearly intended: DO 10 I = 1, 10 After changing the . to a , the program results were correct to the desired accuracy. Apparently, the program's answers had been "good enough" for the sub-orbital Mercury flights, so no one suspected a bug until they tried to get greater accuracy, in anticipation of later orbital and moon flights. As far as I know, this particular bug was never blamed for any actual failure of a space flight, but the other details here seem close enough that I'm sure this incident is the source of the DO story.

我认为这是一个很大的WTF，如果DO10I被作为DO10I，并且反过来，因为隐式声明被认为是类型REAL。这是个很棒的故事。

在C:

warning C4013: 'myfunc' undefined; assuming extern returning int

我记得由于某些原因没有看到警告(在一些遗留代码中有太多警告?)，并且困惑于为什么从int转换会在使用非int返回函数时导致编译器错误。

编译器假设这样的东西是相当出乎意料的。

在JavaScript中:

2 == [2]

// Even stranger
2 == [[[2]]]

// And down-right nutty
var a = { "abc" : 1 };
a[[[["abc"]]]] === a["abc"]; // this is also true

幸运的是，stackoverflow.com网站上善良的人们向我解释了这一切: 为什么2 ==[2]在JavaScript?