diff --git a/Big_Countries.sql b/Big_Countries.sql
new file mode 100644
index 0000000..2f586d5
--- /dev/null
+++ b/Big_Countries.sql
@@ -0,0 +1 @@
+SELECT name, population, area FROM World WHERE population >= 25000000 OR area >= 3000000
\ No newline at end of file
diff --git a/Delete_Duplicate_Emails.sql b/Delete_Duplicate_Emails.sql
new file mode 100644
index 0000000..c973509
--- /dev/null
+++ b/Delete_Duplicate_Emails.sql
@@ -0,0 +1 @@
+DELETE p1 FROM person p1 JOIN person p2 WHERE p1.email = p2.email AND p1.id > p2.id
\ No newline at end of file
diff --git a/Nth_Highest_Salary.sql b/Nth_Highest_Salary.sql
new file mode 100644
index 0000000..f36e5a6
--- /dev/null
+++ b/Nth_Highest_Salary.sql
@@ -0,0 +1,11 @@
+CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
+BEGIN
+  RETURN (
+      # Write your MySQL query statement below.
+        WITH CTE AS(
+            SELECT * , DENSE_RANK() OVER (ORDER BY salary DESC) AS rnk FROM employee
+
+        )
+        SELECT DISTINCT IFNULL(salary, null) FROM CTE WHERE rnk = N
+  );
+END
\ No newline at end of file