Create find-the-start-and-end-number-of-continuous-ranges.sql

Author: kamyu104

MySQL/find-the-start-and-end-number-of-continuous-ranges.sql

@@ -0,0 +1,16 @@
+# Time:  O(n)
+# Space: O(n)
+
+SELECT Min(log_id) AS start_id, 
+       Max(log_id) AS end_id 
+FROM   (SELECT log_id, 
+               @rank := CASE 
+                          WHEN @prev = log_id - 1 THEN @rank 
+                          ELSE @rank + 1 
+                        end    AS rank, 
+               @prev := log_id AS prev
+        FROM   logs AS A, 
+               (SELECT @rank := 0, 
+                       @prev :=- 1) AS B) C 
+GROUP  BY C.rank 
+ORDER  BY NULL;