feat: add sql solution to lc problem: No.1484 (doocs#777)

No.1484.Group Sold Products By The Date

Author: Dhoni77

solution/1400-1499/1484.Group Sold Products By The Date/README.md

@@ -64,7 +64,16 @@ Result 表：
 ### **SQL**
 
 ```sql
-
+SELECT 
+    sell_date,
+    COUNT(DISTINCT product) AS num_sold,
+    GROUP_CONCAT(DISTINCT product
+        ORDER BY product ASC
+        SEPARATOR ',') AS products
+FROM
+    Activities
+GROUP BY sell_date
+ORDER BY sell_date ASC;
 ```
 
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solution/1400-1499/1484.Group Sold Products By The Date/README_EN.md

@@ -65,7 +65,16 @@ For 2020-06-02, the Sold item is (Mask), we just return it.
 ### **SQL**
 
 ```sql
-
+SELECT 
+    sell_date,
+    COUNT(DISTINCT product) AS num_sold,
+    GROUP_CONCAT(DISTINCT product
+        ORDER BY product ASC
+        SEPARATOR ',') AS products
+FROM
+    Activities
+GROUP BY sell_date
+ORDER BY sell_date ASC;
 ```
 
 <!-- tabs:end -->

solution/1400-1499/1484.Group Sold Products By The Date/Solution.sql

@@ -0,0 +1,10 @@
+SELECT 
+    sell_date,
+    COUNT(DISTINCT product) AS num_sold,
+    GROUP_CONCAT(DISTINCT product
+        ORDER BY product ASC
+        SEPARATOR ',') AS products
+FROM
+    Activities
+GROUP BY sell_date
+ORDER BY sell_date ASC;