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关于【SQL优化】中-【不要让数据库帮我们做强制类型转换】和【如果需要进行 join 的字段两表的字段类型要相同】的一点疑问 about jcsprout HOT 2 OPEN

liueleven commented on June 8, 2024

关于【SQL优化】中-【不要让数据库帮我们做强制类型转换】和【如果需要进行 join 的字段两表的字段类型要相同】的一点疑问

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MengXiangDing commented on June 8, 2024

hi,我的MySQL版本是8.0.18
对于你的这个结论：( 结论：隐式转换，where column_name=2 id是字符串类型，相当于使用字符串转整型，不用索引；而整数转字符串会用到索引 ) ，在我这个版本好像是反的。

第一个是整数转字符串，没用到索引。第二个是字符串(也就是说没有隐式转换)，用到了索引

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MengXiangDing commented on June 8, 2024

这是表的字段说明

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