28 lines
789 B
Markdown
28 lines
789 B
Markdown
---
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title: "ClickHouse 表引擎之 Join"
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date: 2020-10-08T17:40:00+08:00
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lastmod: 2020-10-08T17:40:00+08:00
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tags: []
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categories: ["clickhouse"]
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---
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# Join 表引擎简介
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- 数据先写内存，再同步到磁盘，服务重启后全量加载到内存
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- 与 Set 表引擎共用大部分处理逻辑
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- 简单封装了一层 JOIN 查询，主要用做 JOIN 查询
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# 创建 Join 引擎表
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- 声明
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```sql
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ENGINE = Join(join_strictness, join_type, key1[, key2, ...])
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```
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- join_strictness: 连接精度，支持 ALL、ANY 和 ASOF
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- join_type: 连接类型，支持 INNRE、OUTER、CROSS
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- key1, key2 ...: 连接键，关联字段
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- 如果连接精度是 ANY，写入数据时会忽略连接键相同的数据
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# 参考
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- [ClickHouse 表引擎之 Join](/post/ch-search/#JOIN)
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