COMP3910: Coursework 2Submission: GradescopeDeadline: 17:00 GMT, Friday 25 March 2022Award: This piece of summative coursework is worth 10% of your gradeProblem 1 (modelling) [12 marks]A company needs to purchase components X and Y to produce toys. Components X and Y canbe purchased from three su...

1、查询课程编号为01的课程比02的课程高的所有学生的学号和成绩解题思路：(1) 先把课程为01的学号和成绩找出来 as 表a(2) 再把课程为02的学号和成绩找出来 as 表b(3) 用inner join将表a和表b按照s_id连接起来(4) 最后用where筛选表a成绩大于表b成绩的学生编号

需要做多次的 Group By 才能得到: {代码...}

This will add /opt/local/bin to the executable path and make your port command available to the shell.

理论上，家在 GROUP BY 之后 {代码...}

MySQL语法入门（二）数据库加密函数 {代码...} 控制流函数 {代码...} 格式化函数和类型转换函数 {代码...}

select id from table 返回的是一个字符串SQL相当于执行的mysql select * from table in( "a,b,c")预期的是：mysql select * from table in( "a", "b", "c")所以查询出来会有问题

在kingshard开源之后，有用户多次提到能不能在kingshard中加入SQL黑名单机制，让kingshard能够根据特定的规则来拦截在黑名单中的SQL。有几个比较典型的应用场景：

先做group by分组，找到最后一门课更新时间，然后根据stu_id和更新时间找到最新的选课记录，最后和student和subject表做连接

University of EdinburghSchool of InformaticsINFR11199 - Advanced Database Systems (Spring 2021)Coursework AssignmentDue: Thursday, 18 March 2021 at 4:00pmIMPORTANT:• Plagiarism: Every student has to work individually on this project assignment.All of the code for this project must be your own. Yo...

COMP3910: Coursework 2Submission: GradescopeDeadline: 17:00 GMT, Friday 25 March 2022Award: This piece of summative coursework is worth 10% of your gradeProblem 1 (modelling) [12 marks]A company needs to purchase components X and Y to produce toys. Components X and Y canbe purchased from three su...

如果数据类型相似,可以使用as配合union来结合,例如select c1 as a,c2 as b,null as c from t1 unionselect cc1 as a,cc2 as b,cc3 as c from t2;其中,使用null来确保连个select有相同的列数.前提是两个select选择的同一列的数据类型相似.

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我要在三个表中找一条符合条件的记录，比如在第 A 表中找到了，则不需要继续往下找 B表，C表。我现在的语句是这样的，请问可以做到吗? 不写 if else 的那种

yii2 多表联查 where条件里 A表字段=B表字段怎么表示？ {代码...} 想在where条件里加上c.type=b.type怎么加？？？

Enrolment number (student number):The University of MelbournePractice Exam PaperSchool of Computing and Information SystemsCOMP90038 Algorithms and ComplexityReading Time: 15 minutesExam Duration: 3 hoursThis paper has 11 pages, including this front page.Authorised Materials:None. This is a close...