[doc] update substring.md (#8398)

correct a slip of pen.
2022-03-09 13:07:32 +08:00
parent 25532c65d1
commit 97020bcf80
1 changed files with 1 additions and 1 deletions
--- a/docs/zh-CN/sql-reference/sql-functions/string-functions/substring.md
+++ b/docs/zh-CN/sql-reference/sql-functions/string-functions/substring.md
@ -40,7 +40,7 @@ under the License.
 ## example

 ```
-mysql> select substring('abc1', -2);
+mysql> select substring('abc1', 2);
 +-----------------------------+
 | substring('abc1', 2)        |
 +-----------------------------+