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导读执行计划中看到key_len值发生变化，表示联合索引有时能用到多个列，有时却只能用到部分列，这是为啥子呢？我的朋友小明同学这几天又遇到一件令人懵*的事，有个SQL执行计划看起来挺诡异的，我看了下，也是有点发懵。基本信息严格遵循我自己要求的“提问的艺术”，先交代下必要的背景信息。1、表DDL（建议手机横过来观看）[root@yejr.me]>show create table t_key....

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相似的SQL执行计划key_len为什么不同

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更新时间 2022-08-30 14:03:56

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