是否有(大致)SQL或类似xquery的语言来查询JSON?
我正在考虑非常小的数据集，很好地映射到JSON，它将很容易回答查询，如“X的所有值是什么，Y > 3”或做通常的SUM / COUNT类型操作。
作为一个完全虚构的例子，是这样的:
[{"x": 2, "y": 0}}, {"x": 3, "y": 1}, {"x": 4, "y": 1}]
SUM(X) WHERE Y > 0 (would equate to 7)
LIST(X) WHERE Y > 0 (would equate to [3,4])
我认为这将在客户端和服务器端工作，结果将被转换为适当的特定于语言的数据结构(或者可能保留为JSON)
快速搜索一下谷歌，就会发现人们已经考虑过它并实现了一些东西(JAQL)，但它似乎还没有一个标准的用法或库集出现。虽然单独实现每个功能都是相当琐碎的，但如果有人已经做对了，我就不想重新发明轮子。
有什么建议吗?
Edit: This may indeed be a bad idea or JSON may be too generic a format for what I'm thinking.. The reason for wanting a query language instead of just doing the summing/etc functions directly as needed is that I hope to build the queries dynamically based on user-input. Kinda like the argument that "we don't need SQL, we can just write the functions we need". Eventually that either gets out of hand or you end up writing your own version of SQL as you push it further and further. (Okay, I know that is a bit of a silly argument, but you get the idea..)
谷歌有一个项目叫lovefield;刚刚发现了它，它看起来很有趣，尽管它比键入下划线或lodash更复杂。
https://github.com/google/lovefield
Lovefield是一个用纯JavaScript编写的关系查询引擎。它
还提供了在浏览器端持久化数据的帮助。
使用IndexedDB本地存储数据。它提供了类似sql的语法和
跨浏览器工作(目前支持Chrome 37+， Firefox 31+， IE
10+， Safari 5.1+…
这个领域最近出现的另一个有趣的条目叫做jinqJs。
http://www.jinqjs.com/
简单回顾一下示例，它看起来很有前途，API文档似乎写得很好。
function isChild(row) {
return (row.Age < 18 ? 'Yes' : 'No');
}
var people = [
{Name: 'Jane', Age: 20, Location: 'Smithtown'},
{Name: 'Ken', Age: 57, Location: 'Islip'},
{Name: 'Tom', Age: 10, Location: 'Islip'}
];
var result = new jinqJs()
.from(people)
.orderBy('Age')
.select([{field: 'Name'},
{field: 'Age', text: 'Your Age'},
{text: 'Is Child', value: isChild}]);
jinqJs is a small, simple, lightweight and extensible javaScript
library that has no dependencies. jinqJs provides a simple way to
perform SQL like queries on javaScript arrays, collections and web
services that return a JSON response. jinqJs is similar to Microsoft's
Lambda expression for .Net, and it provides similar capabilities to
query collections using a SQL like syntax and predicate functionality.
jinqJs’s purpose is to provide a SQL like experience to programmers
familiar with LINQ queries.
PythonQL提供了一种嵌入式语法，IMHO是对SQL的改进，主要是因为group、window、where、let等可以自由混合。
$ cat x.py
#coding: pythonql
data = [{"x": 2, "y": 0}, {"x": 3, "y": 1}, {"x": 4, "y": 1}]
q = [x match {'x': as x, 'y': as y} in data where y > 0]
print(sum(q))
print(list(q))
q = [x match {'x': as x, 'y': as y} as d in data where d['y'] > 0]
print(sum(q))
这段代码显示了您的问题的两个不同答案，这取决于您需要处理整个结构或仅处理值。执行会给你预期的结果。
$ python x.py
7
[3, 4]
7
当前的Jaql实现目标是使用Hadoop集群进行大型数据处理，因此可能超出了您的需求。然而，它可以在没有Hadoop集群的情况下轻松运行(但仍然需要编译Hadoop代码及其依赖项，其中大部分都包括在内)。Jaql的一个小实现可以嵌入到Javascript和浏览器中，这将是对项目的一个很好的补充。
上面的例子很容易用jaql编写:
$data = [{"x": 2, "y": 0}, {"x": 3, "y": 1}, {"x": 4, "y": 1}];
$data -> filter $.y > 0 -> transform $.x -> sum(); // 7
$data -> filter $.y > 0 -> transform $.x; // [3,4]
当然，还有更多。例如:
// Compute multiple aggregates and change nesting structure:
$data -> group by $y = $.y into { $y, s:sum($[*].x), n:count($), xs:$[*].x};
// [{ "y": 0, "s": 2, "n": 1, "xs": [2] },
// { "y": 1, "s": 7, "n": 2, "xs": [3,4] }]
// Join multiple data sets:
$more = [{ "y": 0, "z": 5 }, { "y": 1, "z": 6 }];
join $data, $more where $data.y == $more.y into {$data, $more};
// [{ "data": { "x": 2, "y": 0 }, "more": { "y": 0, "z": 5 }},
// { "data": { "x": 3, "y": 1 }, "more": { "y": 1, "z": 6 }},
// { "data": { "x": 4, "y": 1 }, "more": { "y": 1, "z": 6 }}]
Jaql可以在http://code.google.com/p/jaql/上下载和讨论
