Merge pull request #285 from Anees1214/main

Why Window Functions Cannot Be Used in WHERE Clauses in SQL

Author: milos-simic

Diff for: data-manipulation/window-functions-where-clause/window-functions-in-where-clause.sql

@@ -0,0 +1,22 @@
+--using a Common Table Expression
+WITH RankedStudents AS (
+    SELECT
+    id, name, gpa,
+    RANK() OVER (ORDER BY gpa DESC) AS r
+FROM Student
+WHERE gpa IS NOT NULL
+)
+SELECT id, name, gpa, r
+FROM RankedStudents
+WHERE r <= 3;
+
+--using a subquery
+SELECT *
+FROM (
+    SELECT 
+        id, name, gpa, 
+        RANK() OVER (ORDER BY gpa DESC) AS r
+    FROM Student
+    WHERE gpa IS NOT NULL
+) AS RankedStudents
+WHERE r <= 3;