52 lines
1.5 KiB
Markdown
52 lines
1.5 KiB
Markdown
---
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{
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"title": "ALTER VIEW",
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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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# ALTER VIEW
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## description
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该语句用于修改一个view的定义
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语法：
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ALTER VIEW
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[db_name.]view_name
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(column1[ COMMENT "col comment"][, column2, ...])
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AS query_stmt
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说明：
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1. 视图都是逻辑上的，其中的数据不会存储在物理介质上，在查询时视图将作为语句中的子查询，因此，修改视图的定义等价于修改query_stmt。
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2. query_stmt 为任意支持的 SQL
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## example
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1、修改example_db上的视图example_view
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ALTER VIEW example_db.example_view
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(
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c1 COMMENT "column 1",
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c2 COMMENT "column 2",
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c3 COMMENT "column 3"
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)
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AS SELECT k1, k2, SUM(v1) FROM example_table
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GROUP BY k1, k2
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