| <!-- |
| |
| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License. |
| |
| --> |
| |
| # Data query |
| |
| There are several types of data queries |
| |
| * Raw data query |
| * Aggregate query |
| * Downsampling query |
| * Single point supplementary null query |
| * Latest data query |
| * Align by device query |
| * Group by fill query |
| |
| In order to achieve the above kinds of queries, a basic query component for a single time series is designed in the IoTDB query engine, and on this basis, various query functions are implemented. |
| |
| ## Related documents |
| |
| * [Query fundamentals](../DataQuery/QueryFundamentals.md) |
| * [Basic query components](../DataQuery/SeriesReader.md) |
| * [Raw data query](../DataQuery/RawDataQuery.md) |
| * [Aggregate query](../DataQuery/AggregationQuery.md) |
| * [Downsampling query](../DataQuery/GroupByQuery.md) |
| * [Recent timestamp query](../DataQuery/LastQuery.md) |
| * [Align by device query](../DataQuery/AlignByDeviceQuery.md) |
| * [Fill function](../DataQuery/FillFunction.md) |
| * [Group by fill query](../DataQuery/GroupByFillQuery.md) |
