diff --git a/README.md b/README.md index 7b506fe..9d455bb 100644 --- a/README.md +++ b/README.md @@ -1,5 +1,43 @@ # Sql1 1. Problem 1: Big Countries (https://leetcode.com/problems/big-countries/) + + --Solution + + SELECT name, + population, + area + FROM world + WHERE area >= 3000000 + OR population >= 25000000; + 2. Problem 2: Nth Highest Salary (https://leetcode.com/problems/nth-highest-salary/) + + --Solution + + CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT + BEGIN + RETURN ( + # Write your MySQL query statement below. + SELECT DISTINCT IFNULL(salary,null) + FROM (SELECT salary, + DENSE_RANK() OVER(ORDER BY salary DESC) AS rnk + FROM employee + ) a + WHERE rnk = N + ); + END + 3. Problem 3: Delete Duplicate Emails (https://leetcode.com/problems/delete-duplicate-emails/) + + --Solution + + DELETE FROM person + WHERE id NOT IN + (SELECT DISTINCT id FROM + (SELECT id, + email, + ROW_NUMBER() OVER(PARTITION BY email ORDER BY id) rwn + FROM person) a + WHERE rwn = 1 + ); \ No newline at end of file