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MySQL 8.0 加了联合索引查询反而更慢：3 种失效与回表实测

本内容遵循CC 4.0 BY-SA版权协议 本文深入分析MySQL 8.0中联合索引查询反而变慢的三大核心原因：最左前缀断裂、隐式类型转换、非覆盖索引导致的回表开销。结合EXPLAIN与性能计数器，量化扫描行 ...
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Every incident leaves evidence.

AI investigator for production incidents. Every incident leaves evidence. - yinx0004/yuanfang ...
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mariadb-to-redshift.mdx

A 2-table MariaDB 11.8 database (8 customers, 40 orders) synced with Full Refresh + CDC and positional deletes as the Iceberg update/delete format into the AWS Glue Data Catalog on S3, then 7 inserts ...
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MySQL简单入门教程

【本文由小黑盒作者@AliceDrop于10月26日发布，转载请标明出处！】 安装与配置 直接在官网下载即可。macOS也可以在brew下载，不过配置起来可能会不太一样。 打开安装包一路下一步即可。

Record of Consolidating Old PHP Sites to a New VPS (2/4): Emergency Fixes for Running Old PHP and Database Migration

Note: This is a record of the work done in my environment. The new server was Ubuntu 26.04 / Apache 2.4.66 / PHP 8.5 / MySQL ...

SQL NULL Pitfalls: Why NOT IN Returns Zero Results and 3 Points Where MySQL and Oracle Behaviors Diverge

Introduction"I want to list customers who haven't ordered, but I get zero results," or "The count doesn't match when I exclude cancellations." Among SQL bugs, those caused by NULL are often discovered ...
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MySQL 表的约束详解：从空属性到外键

本内容遵循CC 4.0 BY-SA版权协议 在 MySQL 中，真正约束字段的是数据类型，但数据类型约束很单一，无法满足复杂的业务需求。比如一个 email 字段要求唯一，或者一个班级名字段不允许为空，这些 ...