diff --git "a/data/3.MySQL\351\253\230\351\230\266/1.\346\267\261\345\205\245\347\264\242\345\274\225/4.\347\273\204\345\220\210\347\264\242\345\274\225/combinate.md" "b/data/3.MySQL\351\253\230\351\230\266/1.\346\267\261\345\205\245\347\264\242\345\274\225/4.\347\273\204\345\220\210\347\264\242\345\274\225/combinate.md"
index 82d1b5aa5c7c5084cffdcd549b9ea8240e4df0b4..7b2d5d816af480b39ff4a0cdc2b5132f17350826 100644
--- "a/data/3.MySQL\351\253\230\351\230\266/1.\346\267\261\345\205\245\347\264\242\345\274\225/4.\347\273\204\345\220\210\347\264\242\345\274\225/combinate.md"
+++ "b/data/3.MySQL\351\253\230\351\230\266/1.\346\267\261\345\205\245\347\264\242\345\274\225/4.\347\273\204\345\220\210\347\264\242\345\274\225/combinate.md"
@@ -27,7 +27,7 @@ Joe 应该如何优化？
 ## 答案
 
 ```sql
-alter table goods add index (`stock-id`, category_id, name);
+alter table goods add index (stock, category_id, name);
 ```
 
 ## 选项
@@ -35,7 +35,7 @@ alter table goods add index (`stock-id`, category_id, name);
 ### A
 
 ```sql
-alter table goods add index (`stock-id` and category_id and name);
+alter table goods add index (stock and category_id and name);
 ```
 
 ### B
@@ -47,5 +47,5 @@ alter table goods add index (concat(stock, category_id, name));
 ### C
 
 ```sql
-alter table goods add index (`stock-id` + category_id + name);
+alter table goods add index (stock + category_id + name);
 ```