随笔分类 - 数据库
摘要:难度:难表Employee: 1 +----+-------+--------+--------------+ 2 | Id | Name | Salary | DepartmentId | 3 +----+-------+--------+--------------+ 4 | 1 | Joe...
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摘要:难度:中等写一段SQL查询至少连续出现3次的数字。+----+-----+| Id | Num |+----+-----+| 1 | 1 || 2 | 1 || 3 | 1 || 4 | 2 || 5 | 1 || 6 | 2 || 7 | 2 |+----...
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摘要:难度:中等写一段SQL语句查询分数排名情况。如果两个分数相等,则排名相同。+----+-------+| Id | Score |+----+-------+| 1 | 3.50 || 2 | 3.65 || 3 | 4.00 || 4 | 3.85 || 5 | 4.00 ||...
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摘要:难度:容易写一段SQL,从表Employee查询第二高的收入。+----+--------+| Id | Salary |+----+--------+| 1 | 100 || 2 | 200 || 3 | 300 |+----+--------+例如,上面数据中第二高的收入...
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摘要:难度:容易给定Customers和Orders两个表,写一段SQL查询所有没有订购记录的客户。表:Customers.+----+-------+| Id | Name |+----+-------+| 1 | Joe || 2 | Henry || 3 | Sam || 4 | ...
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摘要:难度:容易给定表Weather,写一段SQL查询所有前一天温度高过当天温度的记录Id。+---------+------------+------------------+| Id(INT) | Date(DATE) | Temperature(INT) |+---------+----------...
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摘要:难度:容易写一段SQL语句,从表Person中删除所有重复的email记录,只保留最小Id的那条记录。+----+------------------+| Id | Email |+----+------------------+| 1 | john@example.com ...
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摘要:难度:中等表Employee保存了所有的员工数据。+----+-------+--------+--------------+| Id | Name | Salary | DepartmentId |+----+-------+--------+--------------+| 1 | Joe ...
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摘要:难度:容易写一段SQL,在表Person中查找所有重复的Email地址。+----+---------+| Id | Email |+----+---------+| 1 | a@b.com || 2 | c@d.com || 3 | a@b.com |+----+---------+例如...
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