设计表

4.按专业统计课程数量:

sql
SELECT Major, COUNT(*) AS Num 
FROM Course 
GROUP BY Major

5.按专业查询所有课程信息:

sql
SELECT * FROM Course WHERE Major = '信息技术'

6.统计“信息技术”专业的课程数量:

sql
SELECT COUNT(*) FROM Course WHERE Major = '信息技术'

7.按学分将“信息技术”专业的课程排序:

sql
SELECT * FROM Course WHERE Major = '信息技术' 
ORDER BY Credit DESC

8.统计“信息技术”专业课程的平均学时:

sql
SELECT AVG(Period) AS AvgPeriod 
FROM Course 
WHERE Major = '信息技术'

9.查询“信息技术”专业,学时最长的课程信息:

sql
SELECT * FROM Course
WHERE Major = '信息技术' AND Period = (
    SELECT MAX(Period) FROM Course WHERE Major = '信息技术'
)