Oracle SQL

DUAL表。 不能通过别名分组。 我永远记不住分析函数的语法，所以我忘记/懒得使用它们。 缺少组合的LIKE和IN条件运算符。(不过，在10g之后，有一个REGEX_LIKE操作符可以做到这一点。) 笨拙的连接语法。

SQL并不是我最喜欢的语言，但它是我每天使用的三大语言之一。可能还有更多的项目，但这些是我脑海中最重要的。

我有一大堆SQL*PLUS的问题。我写了一个Perl的替代品，从命令行做我想做的，我使用sql。Emacs中的el用于交互式SQL会话。这些工具可以帮助我解决SQL*PLUS问题。

说到这里:

Perl

"Only perl can parse Perl." (But this is mostly an issue in syntax highlighting, which I don't prefer to use much anymore for any language.) I'm sometimes surprised by "the simple (but occasionally surprising) rule...: It looks like a function, therefore it is function, and precedence doesn't matter." (From perlfunc(1)) Dereferencing complex data structures can be confusing at times. I can't decide if this is a true flaw in Perl or just a consequence of having really powerful data structure facilities. Either way, I can normally get it right by taking a few minutes to think about what I'm doing. No option to cause system calls to raise their errors like the DBI module. (Thanks to brian d foy, I now know the autodie module on CPAN does this, but I'd like it built-in.) Warnings and strictures not enabled by default in scripts. (The -e option would turn them off for command line use.)

同样，肯定还有更多的事情，但这些是我最近注意到的问题。我还要加上=over and =back和古怪的L<…>语法在POD中，但也许那应该是一个单独的列表。

现在来看看三连冠:

康壳牌

Sourcing a file with arguments replaces the values of the parent script's arguments. (Executing . file arg1 puts arg1 in $1.) ksh is not an ideal interactive shell and defaults to vi key-bindings, rather than emacs. (My solution is to use bash for interactive shells.) Common utilities (such as grep) are implemented differently across different platforms thereby preventing perfect portability. Some useful commands need to be installed on some platforms and are part of the OS core on others. The syntax for conditionals is overly heavy. (if [ ... ]; then ... fi) Although it is Turing Complete, you are eventually going to want to move up to a more expressive language like Perl.

第4个问题的一个解决方案是习惯短路评估:

[ ... ] && ...

Emacs Lisp

目前还没有足够的商业市场让人们全职用elisp编码 GNU Emacs vs XEmacs不兼容 Scheme中的嵌套函数很整洁，我希望elisp有[1]的概念 用于简单遍历列表的do循环或其他一些工具不是标准的(当然，您现在可以使用lambda进行映射)[1] (function (lambda(…)))[1]应该有一个简写

当然，Lisp的一个美妙之处在于，用一行代码在你自己的代码中修复这些问题并不难。但这并不是与生俱来的，这让我很恼火。

好的问题;我有点不好意思，因为我想不出更好的东西来恨，但说实话，法官大人，没什么好恨的。

很多人认为Java很慢，但我同意一定程度的使用。

Java是戏剧性的。他们为你想做的一件事提供了很多课程。但是你知道灵活性属性XD。

Java一开始很难，但总是很有趣。

当你写一个简单的代码打印“Hello,World!”请不要使用java !XD我相信我是有道理的。

Java是一种混合，所以不要说它是纯粹的面向对象语言。

还有很多，但我只局限于5个XD。谢谢!

我刚刚发现，在c#中创建泛型方法时，我不能使用Enum作为类型约束。

微软有一个足够好的解释，但仍然。我疯了

public static T MyFunc<T>(string arg) where T:Enum //wont work :(

第一个帖子，所以对我放松点:)…很棒的社区网站，顺便说一句!

我试着阅读其他所有的c#回复，这样我的回复就不会重叠了

c#……排名不分先后:

1) switch语句中的case没有fallthrough。如果没有转机……为什么必须显式的类型中断;呢?这只是弱智和令人困惑，因为它意味着没有休息的能力;!!

2)不能在子作用域中声明同名变量，但可以声明与类变量同名的变量?要么都允许，要么都不允许。否则，就没有意义了。

3)函数中没有可选/默认参数

4) finally{}中的异常应该隐式地捕捉每一行。或者至少，只有NullReferenceException异常。例如，在访问数据库后，应该总是清理。所以，finally块应该看起来像这样:

finally
{
  if(par1 != null)
    par1.Dispose();
  if(comm != null)
    comm.Dispose();
  if(conn != null)
    conn.Dispose();
}

如果可以写成这样，就会简洁得多:

finally
{
    par1.Dispose();
    comm.Dispose();
    conn.Dispose();
}

但是，不……你必须检查你是否正在访问一个空对象，否则它可能会从finally块抛出一个NullReferenceException。谁真的需要finally块中的异常呢?

5)泛型:你可以指定new()来实例化你的泛型对象，但是这个对象需要有一个默认构造函数。为什么不能指定一个签名，这样就不需要在还没有空构造函数的情况下创建空构造函数，而只使用已有的构造函数。

C#

Reference types are nullable by default; in-language null keyword is untyped. Lack of discriminated unions Exceptions as default, non-exceptional error handling method - there's not much of an alternative. archaic switch statement syntax and limitations Needless distinction between constructors + static methods Static methods can't be part of an interface Lack of by-shape interface implementation rather than explicit interface implementation - leading to numerous language design hacks such as the linq query syntax, foreach, collection & object initializers -- none of which can be flexibly reused. For example, the object initializer syntax may be nice, but plays poorly with immutable objects. Cannot inherit "interface" of a class independently of implementation - leading to code duplications and overarchitected code that provides interfaces, abstract base classes, a few common implementations, and no way to pick and choose the bits of each to use. Also; leads to too many code that's tightly coupled to a particular implementation since it's common to explicitly refer to the implementation type rather than an interface. Cannot multiply inherit via composition since a classes "interface" is tightly coupled to it's implementation; effectively lack of mixins. The above limitations of interfaces lead to a proliferation of virtually identical interfaces that don't overlap naturally in any kind of type hierarchy. IComparable vs. IEquatable vs. IComparable<T> vs object.Equals vs. operator == etc. etc. By extension, making a custom type that satisfies all these things is a lot more work than necessary (in particular for collection classes). Obviously, the language designers realize this, hence the various workarounds for things like linq, foreach and collection initializers which work by-shape rather than by-interface. Redundant use of parentheses and braces rather than layout-is-structure. Return values can be ignored, limiting the effectiveness of type inference. Enums aren't a normal type and can't have methods. Also, enum values aren't typesafe and may be initialized to 0 despite not having a 0 value. Mixing metaphors by lumping flag and non-flag enums together. Lack of proper value type support. Value types can't be inherited, have different constructor semantics, and perform poorly due to CLR limitations. Also, confusing semantics regarding value types: some values are really values (and can't be modified), and others are really non-aliased, non-null references (variables). This gets particularly confusing with regards to the next issue: Semantic distinction between fields and properties, particularly in conjunction with lack of mutability modifier (ala C++'s const) Can't specialize generics Cannot provide default generic type parameters (e.g. factory generics) lack of typedef makes generics a pain to use (using is a limited but good-to-know substitute!) Can't genericize over things other than types (e.g. functions, plain values, or names). This means you can't do something like make a generic implementation of a dependancy property leading to, well, nasty implementations of things like dependancy properties and the overuse of code-snippets and poorly readable code as a result. Limited capability to specify generic type requirements e.g. generic sum method that takes both int, double and a bigint (without tricky and often slow hacks). An interface method implementation or virtual method override cannot return a more specific type or accept a more general type; i.e. limited co/contravariance support even in C# 4.