我很难在一个栏目中显示学生正在选修的课程数量。FROM Student GROUP BY Student.Student_ID, Student.First_Name, Student.Last_Name 创建一个视图调用BUSY_STUDENT,为所有注册超过2个班级的学生存储连接的姓名(名字和姓氏)、学生id</
有办法消除重复的函数调用吗?select * from v_Booking where ITEM_CODE in( (select count(*) from f_BookingsForSpecialGroup(g.SPECIAL_GROUP_IDIS_BAD=0) as NON_BAD_BOOKINGS,
(select count
message: To be consistent with reshape2's melt, id.varsAll non-numeric/integer/logical type columns are conisdered id.vars, which in this case are columns [Consider providing at least one of 'i