fix: update sql solution to lc problem: No.1211 (#2690)

Author: Professorx911

solution/1200-1299/1211.Queries Quality and Percentage/README.md

@@ -94,9 +94,31 @@ SELECT
     ROUND(AVG(rating / position), 2) AS quality,
     ROUND(AVG(rating < 3) * 100, 2) AS poor_query_percentage
 FROM Queries
+WHERE query_name IS NOT NULL
 GROUP BY 1;
 ```
 
+```sql
+# Write your MySQL query statement below
+SELECT
+    IFNULL(query_name, 'null') AS query_name,
+    ROUND(AVG(CAST(rating AS DECIMAL) / position), 2) AS quality,
+    ROUND(
+        (
+            SUM(
+                CASE
+                    WHEN rating < 3 THEN 1
+                    ELSE 0
+                END
+            ) / NULLIF(COUNT(*), 0)
+        ) * 100,
+        2
+    ) AS poor_query_percentage
+FROM Queries
+GROUP BY query_name WITH ROLLUP
+HAVING query_name IS NOT NULL;
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

solution/1200-1299/1211.Queries Quality and Percentage/README_EN.md

@@ -91,9 +91,31 @@ SELECT
     ROUND(AVG(rating / position), 2) AS quality,
     ROUND(AVG(rating < 3) * 100, 2) AS poor_query_percentage
 FROM Queries
+WHERE query_name IS NOT NULL
 GROUP BY 1;
 ```
 
+```sql
+# Write your MySQL query statement below
+SELECT
+    IFNULL(query_name, 'null') AS query_name,
+    ROUND(AVG(CAST(rating AS DECIMAL) / position), 2) AS quality,
+    ROUND(
+        (
+            SUM(
+                CASE
+                    WHEN rating < 3 THEN 1
+                    ELSE 0
+                END
+            ) / NULLIF(COUNT(*), 0)
+        ) * 100,
+        2
+    ) AS poor_query_percentage
+FROM Queries
+GROUP BY query_name WITH ROLLUP
+HAVING query_name IS NOT NULL;
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

solution/1200-1299/1211.Queries Quality and Percentage/Solution.sql

@@ -4,4 +4,5 @@ SELECT
     ROUND(AVG(rating / position), 2) AS quality,
     ROUND(AVG(rating < 3) * 100, 2) AS poor_query_percentage
 FROM Queries
+WHERE query_name IS NOT NULL
 GROUP BY 1;

solution/1200-1299/1211.Queries Quality and Percentage/Solution2.sql

@@ -0,0 +1,18 @@
+# Write your MySQL query statement below
+SELECT
+    IFNULL(query_name, 'null') AS query_name,
+    ROUND(AVG(CAST(rating AS DECIMAL) / position), 2) AS quality,
+    ROUND(
+        (
+            SUM(
+                CASE
+                    WHEN rating < 3 THEN 1
+                    ELSE 0
+                END
+            ) / NULLIF(COUNT(*), 0)
+        ) * 100,
+        2
+    ) AS poor_query_percentage
+FROM Queries
+GROUP BY query_name WITH ROLLUP
+HAVING query_name IS NOT NULL;