feat: add sql solution to lc problem: No.0586 (doocs#753)

No.0586.Customer Placing the Largest Number of Orders

Author: Dhoni77

solution/0500-0599/0586.Customer Placing the Largest Number of Orders/README.md

@@ -66,7 +66,13 @@ customer_number 为 '3' 的顾客有两个订单，比顾客 '1' 或者 '2' 都
 ### **SQL**
 
 ```sql
-
+SELECT 
+    customer_number
+FROM
+    Orders
+GROUP BY customer_number
+ORDER BY COUNT(customer_number) DESC
+LIMIT 1;
 ```
 
 <!-- tabs:end -->

solution/0500-0599/0586.Customer Placing the Largest Number of Orders/README_EN.md

@@ -60,7 +60,13 @@ So the result is customer_number 3.
 ### **SQL**
 
 ```sql
-
+SELECT 
+    customer_number
+FROM
+    Orders
+GROUP BY customer_number
+ORDER BY COUNT(customer_number) DESC
+LIMIT 1;
 ```
 
 <!-- tabs:end -->

solution/0500-0599/0586.Customer Placing the Largest Number of Orders/Solution.sql

@@ -0,0 +1,7 @@
+SELECT 
+    customer_number
+FROM
+    Orders
+GROUP BY customer_number
+ORDER BY COUNT(customer_number) DESC
+LIMIT 1;