摘要: 15.4 What are the different types of joins? Please explain how they differ and why certain types are better in certain situations. Join是用来联合两个表的,每个表至少 阅读全文
posted @ 2016-04-05 12:13 Grandyang 阅读(729) 评论(0) 推荐(0)
摘要: The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. Given the Em 阅读全文
posted @ 2016-04-05 11:21 Grandyang 阅读(3884) 评论(0) 推荐(1)
摘要: Write a SQL query to find all numbers that appear at least three times consecutively. For example, given the above Logs table, 1 is the only number th 阅读全文
posted @ 2016-04-05 10:51 Grandyang 阅读(6391) 评论(0) 推荐(0)
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