如何在cosmos DB中计算不同的价值 [英] how to count distinct value in cosmos DB
本文介绍了如何在cosmos DB中计算不同的价值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我在Cosmos DB中创建了一些文档,如下所示:
I created some documents in Cosmos DB like this:
[
{
"class": "class01",
"student": {
"lastReport": [
{
"Name": "st01",
"score": "C"
},
{
"Name": "st02",
"score": "B"
}
],
"lastTime": "2018-05-10"
}
},
{
"class": "class02",
"student": {
"lastReport": [
{
"Name": "st03",
"score": "C"
},
{
"Name": "st01",
"score": "A"
}
],
"lastTime": "2018-05-10"
}
},
{
"class": "class01",
"student": {
"lastReport": [
{
"Name": "st01",
"score": "C"
},
{
"Name": "st02",
"score": "A"
},
{
"Name": "st03",
"score": "B"
}
],
"lastTime": "2018-05-10"
}
}
]
您能帮我如何计算所有数据中的得分值吗?我的期望是这样的结果:
Could you help me how to count value of score in all data? My expectation is the result like this:
[
{
"score": "C",
"Num" : 3
},
{
"score": "B",
"Num" : 2
},
{
"score": "A",
"Num" : 2
}
]
推荐答案
正如@Sajeetharan所说,到目前为止,azure cosmos db不支持group by.但是,我建议您使用存储过程
来实现您的要求.
As @Sajeetharan said, group by is not supported by azure cosmos db so far. However , I suggest you using Stored Procedure
to implement your requirement.
根据您的示例文档,我为您提供了一个示例存储过程.请参考.
Base on your sample documents, I provide you with a sample stored procedure. Please refer to it.
function sample() {
var collection = getContext().getCollection();
var isAccepted = collection.queryDocuments(
collection.getSelfLink(),
'SELECT a.score FROM c join a in c.student.lastReport',
function (err, feed, options) {
if (err) throw err;
if (!feed || !feed.length) getContext().getResponse().setBody('no docs found');
else {
var map = {};
var returnResult = [];
for(var i = 0;i<feed.length;i++){
var s = feed[i].score;
if(map.hasOwnProperty(s)){
map[s] ++;
}else {
map[s] = 1;
}
}
for(var key in map){
console.log(key)
var obj = {
"score":key,
"num" : map[key]
};
returnResult.push(obj);
}
getContext().getResponse().setBody(returnResult);
}
});
if (!isAccepted) throw new Error('The query was not accepted by the server.');
}
输出:
Output :
希望它对您有帮助.
这篇关于如何在cosmos DB中计算不同的价值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文