forked from angelo/java-retail-app
26 lines
720 B
Plaintext
26 lines
720 B
Plaintext
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merge into 用法：（在插入或更新，或者批量更新时，使用 merge into 写法，效率更高）
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Merge into的基本语法：
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语法如下：
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MERGE [INTO [schema .] table [t_alias]
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USING [schema .] { table | view | subquery } [t_alias]
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ON ( condition )
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WHEN MATCHED THEN [merge_update_clause ]
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WHEN NOT MATCHED THEN [merge_insert_clause];
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通俗点就是如下的语法：
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MERGE INTO [表名] [表别名]
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USING ( [查询内容] )[或者像表查询一样的语句]
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ON ([条件表达式] AND [...]...)
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WHEN MATCHED THEN [匹配的update操作]
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WHEN NOT MATCHED THEN [不匹配的insert操作]
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参考：
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https://www.cnblogs.com/onlookers/p/4270418.html
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http://t.zoukankan.com/yhoralce-p-7482614.html
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