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MySQL 中 EXPLAIN 命令详解 - overtrue #23
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翻译得什么呀?贴个原文链接多好 |
sorry, 从很早的笔记里找到的,我也不晓得从哪里来的,翻译的不好,还请大佬多多指教,谢谢! |
超哥,列 type 中的连接类型是eq_ref还是eq_reg? |
应该是 eq_ref |
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https://overtrue.me/articles/2014/10/mysql-explain.html
EXPLAIN 显示了 MySQL 如何使用索引来处理 SELECT 语句以及连接表。可以帮助选择更好的索引和写出更优化的查询语句。 使用方法,在 select 语句前加上EXPLAIN就可以了: 如: EXPLAIN SELECT
surname
,first_name
FORMa
,b
WHEREa
.id
=b
.id
EXPLAIN列的解释: 列 描述 table 显示这一行的数据是关于哪张表的。 type 这是重要的列,显示连接使用了何种类型。从最好到最差的连接类型为 const、eq_reg、ref、range、index和ALL。 possible...The text was updated successfully, but these errors were encountered: