No176-No183(easy SQL)

Author: tujietg

leetcode/SQL/No176.sql

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+select max(e.Salary) as SecondHighestSalary from Employee e
+where e.Salary < (select max(Salary) from Employee);

leetcode/SQL/No181.sql

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+select  e.Name as Employee
+from Employee e 
+join Employee m on e.ManagerId = m.id 
+where e.Salary > m.Salary;

leetcode/SQL/No182.sql

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+select p.Email as Email from Person p group by p.Email having count(p.Email) > 1;

leetcode/SQL/No183.sql

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+select c.Name as Customers from Customers c left join Orders o on c.id = o.CustomerId where o.CustomerId is null;