摘要:
🍀单表优化 【数据准备】 create table book ( bid int(4) primary key, name varchar(20) not null, authorid int(4) not null, publicid int(4) not null, typeid int(4) 阅读全文
posted @ 2021-06-25 23:39
Felix_Openmind
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摘要:
优化的原因: 性能低、执行时间太长、索引失效、服务器参数设置不合理(缓冲、线程数) SQL编写过程 SELECT DISTINCT ... FROM .... JOIN ... ON ... WHERE .... GROUP BY .... HAVING ... ORDER BY ... LIMIT 阅读全文
posted @ 2021-06-25 16:07
Felix_Openmind
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