Completed SQL1

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

bigcountries.sql

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+# Write your MySQL query statement below
+select name,population, area from world where area>=3000000 or population>=25000000;

delete-duplicate-emails.sql

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+# Write your MySQL query statement below
+DELETE FROM PERSON WHERE ID NOT IN (SELECT * FROM (SELECT MIN(ID) FROM PERSON GROUP BY EMAIL) AS EMAIL);