| --- |
| { |
| "title": "STATE", |
| "language": "en" |
| } |
| --- |
| |
| <!-- |
| 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. |
| --> |
| |
| ## STATE |
| |
| ### description |
| #### Syntax |
| |
| `AGGREGATE_FUNCTION_STATE(arg...)` |
| Returns the intermediate result of the aggregation function, which can be used for subsequent aggregation or to obtain the actual calculation result through the merge combiner, or can be directly written into the agg_state type table and saved. |
| The type of the result is agg_state, and the function signature in agg_state is `AGGREGATE_FUNCTION(arg...)`. |
| |
| ### example |
| ``` |
| mysql [test]>select avg_merge(t) from (select avg_union(avg_state(1)) as t from d_table group by k1)p; |
| +----------------+ |
| | avg_merge(`t`) | |
| +----------------+ |
| | 1 | |
| +----------------+ |
| ``` |
| ### keywords |
| AGG_STATE,STATE |
