feat: add sql solution to lc problem: No.2893 (#1896)

Author: thinkasany

solution/2800-2899/2893.Calculate Orders Within Each Interval/README.md

@@ -94,4 +94,13 @@ FROM T
 WHERE minute % 6 = 0;
 ```
 
+```sql
+SELECT
+    FLOOR((minute + 5) / 6) AS interval_no,
+    SUM(order_count) AS total_orders
+FROM Orders
+GROUP BY 1
+ORDER BY 1;
+```
+
 <!-- tabs:end -->

solution/2800-2899/2893.Calculate Orders Within Each Interval/README_EN.md

@@ -84,4 +84,13 @@ FROM T
 WHERE minute % 6 = 0;
 ```
 
+```sql
+SELECT
+    FLOOR((minute + 5) / 6) AS interval_no,
+    SUM(order_count) AS total_orders
+FROM Orders
+GROUP BY 1
+ORDER BY 1;
+```
+
 <!-- tabs:end -->