76 lines
2.1 KiB
Markdown
76 lines
2.1 KiB
Markdown
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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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KIND, either express or implied. See the License for the
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-->
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# CAST
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## description
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### Syntax
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```
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cast (input as type)
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```
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### BIGINT type
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### Syntax(BIGINT)
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``` cast (input as BIGINT) ```
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将 input 转成 指定的 type
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将当前列 input 转换为 BIGINT 类型
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## example
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1. 转常量，或表中某列
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```
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mysql> select cast (1 as BIGINT);
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+-------------------+
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| CAST(1 AS BIGINT) |
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+-------------------+
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| 1 |
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+-------------------+
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```
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2. 转导入的原始数据
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```
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curl --location-trusted -u root: -T ~/user_data/bigint -H "columns: tmp_k1, k1=cast(tmp_k1 as BIGINT)" http://host:port/api/test/bigint/_stream_load
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```
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*注：在导入中，由于原始类型均为String，将值为浮点的原始数据做 cast的时候数据会被转换成 NULL ，比如 12.0 。Doris目前不会对原始数据做截断。*
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如果想强制将这种类型的原始数据 cast to int 的话。请看下面写法：
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```
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curl --location-trusted -u root: -T ~/user_data/bigint -H "columns: tmp_k1, k1=cast(cast(tmp_k1 as DOUBLE) as BIGINT)" http://host:port/api/test/bigint/_stream_load
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mysql> select cast(cast ("11.2" as double) as bigint);
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+----------------------------------------+
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| CAST(CAST('11.2' AS DOUBLE) AS BIGINT) |
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+----------------------------------------+
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| 11 |
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+----------------------------------------+
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1 row in set (0.00 sec)
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```
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##keyword
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CAST
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