Time Series Database:Use the SDK multi-value data model to read data

Sample code

/*
         * Use the multiFieldQuery() API.
         * You can create a request to query multi-value data by using this process: Specify the MultiFieldSubQueryDetails (list) information, create a MultiFieldSubQuery request, and then create a MultiFieldQuery request.
         * You can create multiple subqueries for each multi-value data query.
         *  
         * You must provide the following information when you perform a query:
         * MultiFieldSubQueryDetails: the details of the specific fields for the target metric. The fields are the sub-category of the metric. For example, you can query only the speed or direction fields.
         *                                  You can specify the following parameters: aggregator, dpValue, rate, and downsample.
         * Metric: the metric to be queried, for example, wind.
         *  Time Range: Start Time and End Time
         *
         * The following information is optional:
         * Tags: the conditions that are used to filter timelines.
         * Limit/Offset: the pagination details.
         */
        // Create the fields that you want to query.
        MultiFieldSubQueryDetails speedFieldDetails = MultiFieldSubQueryDetails
                .field("speed").aggregator(Aggregator.SUM).downsample("2s-sum").build();
        MultiFieldSubQueryDetails levelFieldDetails = MultiFieldSubQueryDetails
                .field("level").aggregator(Aggregator.AVG).downsample("2s-avg").build();
        MultiFieldSubQueryDetails tempFieldDetails = MultiFieldSubQueryDetails
                .field("temperature").aggregator(Aggregator.COUNT).downsample("2s-count").build();
        MultiFieldSubQueryDetails allFieldsDetails1 = MultiFieldSubQueryDetails
                .field("*").aggregator(Aggregator.MAX).downsample("2s-max").alias("max_").build();
        MultiFieldSubQueryDetails allFieldsDetails2 = MultiFieldSubQueryDetails
                .field("*").aggregator(Aggregator.MIN).downsample("2s-min").alias("min_").build();
        List<MultiFieldSubQueryDetails> subQueryDetails = new LinkedList<>();
        subQueryDetails.add(speedFieldDetails);
        subQueryDetails.add(levelFieldDetails);
        subQueryDetails.add(tempFieldDetails);
        subQueryDetails.add(allFieldsDetails1);
        subQueryDetails.add(allFieldsDetails2);
        // Create a subquery for the multi-value data model.
        MultiFieldSubQuery subQuery = MultiFieldSubQuery.metric(metric).fieldsInfo(subQueryDetails)
                .filter(Filter.filter(FilterType.LiteralOr, "district", "Yuhang|Xiacheng|Xihu", true).build())
                .build();
        // Create a query for the multi-value data model.
        MultiFieldQuery query = MultiFieldQuery.start(1542772000L).end(1542772020L).msResolution(false)
                .sub(subQuery).build();
        List<MultiFieldQueryResult> results = tsdb.multiFieldQuery(query);