Completed Sql 1

Big_Countries.sql

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+SELECT name, population, area FROM World WHERE population >= 25000000 OR area >= 3000000

Delete_Duplicate_Emails.sql

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+DELETE p1 FROM person p1 JOIN person p2 WHERE p1.email = p2.email AND p1.id > p2.id

Nth_Highest_Salary.sql

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+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