Mongo aggregrate conditional $match, $group and $project

Question

My collection has document structure like below:

{ AppName: 'test',
AppEnv: 'Development'
AppTech:'Java'
AppVersion: '1_0',

AppName: 'test',
AppEnv: 'SQA'
AppTech:'Java'
AppVersion: '1_0',

AppName: 'test22',
AppEnv: 'Development'
AppTech:'Java'
AppVersion: '1_2',

AppName: 'test22',
AppEnv: 'SQA'
AppTech:'Java'
AppVersion: '1_1',

AppName: 'test22',
AppEnv: 'Production'
AppTech:'Java'
AppVersion: '1_0',

AppName: 'test2',
AppEnv: 'Development'
AppTech:'.NET'
AppVersion: '1_0'

}

I need to get AppVersion based on AppName/AppEnv/AppTech provided.For eg:

AppVersion(with some flag) based on AppEnv of all whose AppTech is 'Java'. The result could look like below:

{
AppName: 'test', 
AppTech: 'Java',
VersionInfo: [AppEnv: {'Development','SQA'}, AppVersion: {'1_0','1_1'}],
hasVersionDiff: 'false',

AppName: 'test22', 
AppTech: 'Java',
VersionInfo: [AppEnv: {'Development','SQA','Production}, AppVersion: {'1_2','1_1','1_0'}],
hasVersionDiff: 'true'

}

Can someone please suggest me how do i start writing queries for this?

are you sure for `hasVersionDiff: 'false'` and multi app version in first result record ? — Amir Azizkhani, Jul 22 '19 at 08:26

score 0 · Accepted Answer · answered Nov 30 '18 at 03:39

You can try this one

let query = {AppTech: 'Java'};
let result = await Collection.aggregate([
{ $match: query },
{ $group: { 
    _id: '$AppName', 
    AppTech: {$first: '$AppTech' },
    AppEnv: {$push: '$AppEnv'},
     AppVersion: {$push: '$AppVersion'}} 
},
{
    $project: {
        AppName: '$_id',
        AppTech: '$AppTech',
        VersionInfo: { AppEnv: '$AppEnv', AppVersion: '$AppVersion' }
    }
}

])

I change the format of the output because the format that you expect is not possible. And i didn't include the hasVersionDiff field, you can just add it later.

 {
    AppName: 'test', 
    AppTech: 'Java',
    VersionInfo: {
        AppEnv: ['Development','SQA'], 
        AppVersion: ['1_0','1_1']
    },
},
{
    AppName: 'test22', 
    AppTech: 'Java',
    VersionInfo: {
        AppEnv: ['Development','SQA','Production'],
        AppVersion: ['1_2','1_1','1_0']
    }
}

score 0 · Answer 2 · answered Jul 22 '19 at 09:37

you can use MongoTemplate.

assume your class is like this:

public class OutPutClass {
    String appName;
    String appTech;
    VersionInfo versionInfo;

    public class VersionInfo{

        List<String> appEnvs;
        List<String> appVersions;
    }
}

and mongoTemplate query:

final Criteria criteria =
            Criteria.where("appTech").is("Java");
    Aggregation aggregation = Aggregation.newAggregation(
            Aggregation.match(criteria),
            Aggregation.group("AppName")
                    .first("AppName")
                    .as("appName")
                    .first("AppTech")
                    .as("appTech")
                    .push("AppEnv").as("versionInfo.appEnvs")
                    .push("AppVersion").as("versionInfo.appVersions")
    );

mongoTemplate.aggregate(
                        aggregation,
                        DocumentClass.class,
                        OutputClass.class
                );

Mongo aggregrate conditional $match, $group and $project

2 Answers2