Tracy1226的博客

Qustion1 合并两表：Table: Person+-------------+---------+| Column Name | Type |+-------------+---------+| PersonId | int || FirstName | varchar || LastName | varchar |+-----------...

 问题二：找出第二高工资Write a SQL query to get the second highest salary from the Employee table.+----+--------+| Id | Salary |+----+--------+| 1 | 100 || 2 | 200 || 3 | 300 |+----+----...

问题：查找重复邮箱Write a SQL query to find all duplicate emails in a table named Person.+----+---------+| Id | Email |+----+---------+| 1 | a@b.com || 2 | c@d.com || 3 | a@b.com |+----+-------...

问题：找出班级中超过五个学生的课程There is a table courses with columns: student and classPlease list out all classes which have more than or equal to 5 students.For example, the table:studentclassAMath...

问题一：从titles表获取按照title进行分组，每组个数大于等于2，给出title以及对应的数目t。CREATE TABLE IF NOT EXISTS "titles" (`emp_no` int(11) NOT NULL,`title` varchar(50) NOT NULL,`from_date` date NOT NULL,`to_date` date DEFAULT NU...