feat: add sql solution to lc problem: No.0511 (#770)

No.0511.Game Play Analysis I

Author: Dhoni77

solution/0500-0599/0511.Game Play Analysis I/README.md

@@ -59,7 +59,11 @@ Result 表：
 ### **SQL**
 
 ```sql
-
+SELECT 
+    player_id, MIN(event_date) first_login
+FROM
+    Activity
+GROUP BY player_id;
 ```
 
 <!-- tabs:end -->

solution/0500-0599/0511.Game Play Analysis I/README_EN.md

@@ -60,7 +60,11 @@ Activity table:
 ### **SQL**
 
 ```sql
-
+SELECT 
+    player_id, MIN(event_date) first_login
+FROM
+    Activity
+GROUP BY player_id;
 ```
 
 <!-- tabs:end -->

solution/0500-0599/0511.Game Play Analysis I/Solution.sql

@@ -0,0 +1,5 @@
+SELECT 
+    player_id, MIN(event_date) first_login
+FROM
+    Activity
+GROUP BY player_id;