联盟？ 相交？ 或相交相交？

Question

我正在处理一个select语句，该语句应在每个上学日返回课程。 周期重新开始之前有4个教学日。 （例如，星期一= Day1，星期二= Day2 ...星期四= Day4，星期五= Day1..etc）

有些学生在某些日子可能会有1个休假，在这种情况下，我们应该在该天/该期间组合中显示一个空白处。

目前，select语句仅返回具有值的天。

例：

            Day 1    Day 2    Day 3    Day 4
Period 1    class    class    off      class
Period 2    class    class    class    off
Period 3    off      class    class    class
Period 4    class    off      class    class

我要完成的工作是让select语句返回一个空行（具有空值）来代替某一天关闭的时间段。 我尝试添加以天为唯一值的工会。

这是行不通的，因为我得到的是前3行，然后是其他4行，但是我真正想要的是前3行（例如，第1,3,4天）和最后一个并列的行（例如，第2天），在这种情况下，我可以随后在当天下订单。

我怎样才能做到这一点？ 我应该使用相交吗？ ..或相交的对面？ 这也适用于Oracle数据库。

选择语句：

select spct.course_code||'-'||spct.course_section as course,t.school_cycle_day as jour,p.legal_first_name,p.legal_surname,sc.room_no
from   student_program_class_tracks@trl spct,class_meetings@trl cm,school_classes@trl sc,persons@trl p,timeslots@trl t,school_timeline_periods@trl tsp
where  spct.school_code=cm.school_code
and    spct.school_code=sc.school_code
and    spct.school_code=t.school_code
and    spct.school_code=tsp.school_code
and    spct.school_year=cm.school_year
and    spct.school_year=sc.school_year
and    spct.school_year=t.school_year
and    spct.school_year=tsp.school_year
and    t.school_year_track=tsp.school_year_track
and    t.school_timeline_code=tsp.school_timeline_code
and    t.school_period=tsp.school_period
and    spct.class_code=cm.class_code
and    spct.class_code=sc.class_code
and    sc.reporting_teacher=p.person_id
and    cm.block=t.block
and    spct.school_code='73'
and    spct.school_year='20122013'
and    spct.person_id='000170629'
and    cm.semester='2'
and    cm.term='1'
and    t.school_period='1'
and    ((spct.start_date <= sysdate and spct.end_date >= sysdate) or spct.demit_indicator='0')
--order by t.school_cycle_day

UNION

SELECT '','1','','','' from DUAL

UNION

SELECT '','2','','','' from DUAL

UNION

SELECT '','3','','','' from DUAL

UNION

SELECT '','4','','','' from DUAL;

输出：

Course         Jour    Legal_first_name   Legqal_surname     Room_no
PPL4OO-03      2       François           Belle-Isle     1-139
SBI4UU-02      4       Louise             Bérubé             1-155
TFC4EE-02      3       Gino               Proulx             1-127
           1            

感谢您的任何帮助，您可以提供！

Answer 1

如果您要说的是每个学生要排4行，则应执行以下操作。

SELECT
    B.course
    A.school_cycle_day,
    B.legal_first_name,
    B.legal_surname,
    B.room_no
FROM
    (
        SELECT '1' AS school_cycle_day
        FROM DUAL

        UNION ALL

        SELECT '2'
        FROM DUAL

        UNION ALL

        SELECT '3'
        FROM DUAL

        UNION ALL

        SELECT '4'
        FROM DUAL
    ) A
    LEFT JOIN
   (
      select
           spct.course_code||'-'||spct.course_section as course,
           t.school_cycle_day as jour,
           p.legal_first_name,
           p.legal_surname,
           sc.room_no
      from
           student_program_class_tracks@trl spct,
           class_meetings@trl cm,
           school_classes@trl sc,
           persons@trl p,
           timeslots@trl t,
           school_timeline_periods@trl tsp
      where
           spct.school_code=cm.school_code and
           spct.school_code=sc.school_code and
           spct.school_code=t.school_code and
           spct.school_code=tsp.school_code and
           spct.school_year=cm.school_year and
           spct.school_year=sc.school_year and
           spct.school_year=t.school_year and
           spct.school_year=tsp.school_year and
           t.school_year_track=tsp.school_year_track and
           t.school_timeline_code=tsp.school_timeline_code and
           t.school_period=tsp.school_period and
           spct.class_code=cm.class_code and
           spct.class_code=sc.class_code and
           sc.reporting_teacher=p.person_id and
           cm.block=t.block and
           spct.school_code='73' and
           spct.school_year='20122013' and
           spct.person_id='000170629' and
           cm.semester='2' and
           cm.term='1' and
           t.school_period='1' and
           ((spct.start_date <= sysdate and spct.end_date >= sysdate) or  spct.demit_indicator='0')
) B ON A.school_cycle_day = B.school_cycle_day