1d9b3aeee7
The error format '##keyword' in a lot of docs. This pr is to repair document format. #4335
58 lines
1.6 KiB
Markdown
58 lines
1.6 KiB
Markdown
---
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{
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"title": "AVG",
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"language": "zh-CN"
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}
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---
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<!--
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Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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# AVG
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## description
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### Syntax
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`AVG([DISTINCT] expr)`
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用于返回选中字段的平均值
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可选字段DISTINCT参数可以用来返回去重平均值
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## example
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```
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mysql> SELECT datetime, AVG(cost_time) FROM log_statis group by datetime;
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+---------------------+--------------------+
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| datetime | avg(`cost_time`) |
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+---------------------+--------------------+
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| 2019-07-03 21:01:20 | 25.827794561933533 |
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+---------------------+--------------------+
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mysql> SELECT datetime, AVG(distinct cost_time) FROM log_statis group by datetime;
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+---------------------+---------------------------+
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| datetime | avg(DISTINCT `cost_time`) |
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+---------------------+---------------------------+
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| 2019-07-04 02:23:24 | 20.666666666666668 |
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+---------------------+---------------------------+
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```
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## keyword
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AVG
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