在某些条件下，在SQL选择语句中重复相同的行

Question

我有一个数据库表有四列名为"Courses(CourseID,CourseName,CreditHours,LabSession)"，我想编写SQL语句来检索Course表中的所有数据，此外，如果LabSession列中的SQL必须重复行（记录） row具有值"Y"，否则将按原样检索行而不重复。

BTW，我正在使用Microsoft SQL Server数据库

Answer 1

select CourseID,CourseName,CreditHours,LabSession from Courses
union ALL
select CourseID,CourseName,CreditHours,LabSession from Courses where LabSession='Y'
order by CourseID

Answer 2

SELECT CourseID, CourseName, CreditHours, LabSession
FROM Courses
UNION ALL
SELECT CourseID, CourseName, CreditHours, LabSession
FROM Courses
WHERE LabSession = 'Y'
ORDER BY CourseId