51 lines
1.5 KiB
Markdown
Executable File
51 lines
1.5 KiB
Markdown
Executable File
---
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{
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"title": "PERCENTILE",
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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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# PERCENTILE
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## description
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### Syntax
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`PERCENTILE(expr, DOUBLE p)`
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计算精确的百分位数，适用于小数据量。先对指定列降序排列，然后取精确的第 p 位百分数。p的值介于0到1之间
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参数说明
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expr：必填。值为整数（最大为bigint） 类型的列。
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p：必填。需要精确的百分位数。取值为 [0.0,1.0]。
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## example
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```
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MySQL > select `table`, percentile(cost_time,0.99) from log_statis group by `table`;
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+---------------------+---------------------------+
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| table | percentile(`cost_time`, 0.99) |
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+----------+--------------------------------------+
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| test | 54.22 |
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+----------+--------------------------------------+
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```
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## keyword
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PERCENTILE
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