Update 181._duplicate_emails.md

0xkookoo · web-flow · commit 85fc41368e48 · 2018-06-28T14:37:47.000+08:00
diff --git a/docs/Leetcode_Solutions/181._duplicate_emails.md b/docs/Leetcode_Solutions/181._duplicate_emails.md
@@ -43,3 +43,7 @@ from Person
 group by Email
 having count(1)>1
 ```
+或者
+```sql
+select Email from Person group by Email having count(Email) > 1
+```
