Commit 394a5ed

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fix:少写了一个字

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Original file line number	Diff line number	Diff line change
`@@ -60,7 +60,7 @@ MySQL中的索引可以以一定顺序引用多列,这种索引叫作联合索`
`60`	`60`	```
`61`	`61`	`select * from user where name=xx and city=xx ; //可以命中索引`
`62`	`62`	`select * from user where name=xx ; // 可以命中索引`
`63`		`-select * from user where city=xx; // 法命中索引`
	`63`	`+select * from user where city=xx; // 无法命中索引`
`64`	`64`	```
`65`	`65`	这里需要注意的是,查询的时候如果两个条件都用上了,但是顺序不同,如 `city= xx and name =xx`,那么现在的查询引擎会自动优化为匹配联合索引的顺序,这样是能够命中索引的.
`66`	`66`
@@ -109,4 +109,4 @@ ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3`
`109`	`109`	`- 《Java工程师修炼之道》`
`110`	`110`	`- 《MySQL高性能书籍_第3版》`
`111`	`111`	`- https://juejin.im/post/5b55b842f265da0f9e589e79`
`112`		`-`
	`112`	`+`

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