diff --git a/Problem1_Big Countries.sql b/Problem1_Big Countries.sql
new file mode 100644
index 0000000..c2dfb2a
--- /dev/null
+++ b/Problem1_Big Countries.sql	
@@ -0,0 +1,4 @@
+select name,population,area
+from world
+where area >= 3000000
+or population >= 25000000
\ No newline at end of file
diff --git a/Problem2_NthHighestSalary.sql b/Problem2_NthHighestSalary.sql
new file mode 100644
index 0000000..60c25a1
--- /dev/null
+++ b/Problem2_NthHighestSalary.sql
@@ -0,0 +1,10 @@
+CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
+BEGIN
+  RETURN (
+    with cte as( 
+      select id,salary,dense_rank() over (order by salary desc) as salaryrank from employee
+    )
+    select distinct ifnull(salary,null) as getNthHighestSalary
+    from cte where salaryrank=N
+  );
+END
\ No newline at end of file
diff --git a/Problem3_DeleteDuplicateEmails.sql b/Problem3_DeleteDuplicateEmails.sql
new file mode 100644
index 0000000..d178850
--- /dev/null
+++ b/Problem3_DeleteDuplicateEmails.sql
@@ -0,0 +1,3 @@
+delete p1 
+from person p1 cross join person p2
+where p1.email=p2.email and p1.id>p2.id
\ No newline at end of file