Question

我正在尝试使用Oracle执行SQL分区，因此，应该返回所有已将SAME类作为特定ID教授的User_ID。

我正在使用的两个表的表结构：

HUMAN(id, first, last)
INSTRUCTOR(human_id, location) -- PK(id, location)
CLASS(instructor_id, class_code, class_num) -- PK(instructor_id, class_code, class_num)

我正在使用的查询：

SELECT DISTINCT instructor_id, class_code, class_num
FROM CLASS
WHERE NOT EXISTS (
  (SELECT instructor_id, class_code, class_num FROM CLASS)
  MINUS
  (SELECT instructor_id, class_code, class_num
  FROM CLASS
  WHERE instructor_id =
  (SELECT HUMAN.id
  FROM HUMAN
  WHERE first = 'Foo'
  AND last = 'Bar')))

示例数据

HUMAN  
id   first   last
 1   foo     bar
 2   John    Doe

INSTRUCTOR  
human_id   location   
      1    US
      2    CA

CLASS
instructor_id   class_code    class_num
     1             CS            999
     1             MA            111
     1             DE            222
     2             CS            999
     2             MA            111
     2             DE            222
     3             CS            999
     4             CS            999

查询应该返回instructor_id 2，因为它是唯一指示同一类instructor_id 1

的人

尽管插入数据以匹配此场景，但我的查询没有返回任何行。

Answer 1

SELECT DISTINCT instructor_id, class_code, class_num
 FROM CLASS
WHERE class_num IN (SELECT class_num from CLASS WHERE instructor_id = (SELECT HUMAN.id FROM HUMAN  WHERE first = 'Foo'  AND last = 'Bar'))

这将返回所有教师（包括Foo Bar），这些教师提供与Foo Bar相同的课程。

如果要排除Foo Bar，只需添加另一个WHERE类（instructor_id！=（SELECT HUMAN.id FROM HUMAN WHERE first =＆＃39; Foo＆＃39; AND last =＆＃39; Bar＆＃39;））

Answer 2

其中一种方式：

with t as (
  select distinct instructor_id id, class_num cn
    from class
   where instructor_id = (select id from human
                           where first = 'foo' and last = 'bar'))
select c.instructor_id as id, max(h.first||' '||h.last) as name
  from class c
  join human h on c.instructor_id = h.id
  join t on t.cn = c.class_num and c.instructor_id <> t.id
  group by instructor_id
  having count(distinct class_num) = (select count(1) from t)

测试数据和输出：

create table HUMAN  (id number(3), first varchar2(5), last varchar2(5));
insert into human values (1, 'foo', 'bar');
insert into human values (2, 'John', 'Doe');

create table INSTRUCTOR (human_id number(3), location varchar2(3));
insert into instructor values (1, 'US');
insert into instructor values (2, 'CA');

create table CLASS (instructor_id number(3), class_code varchar2(3), class_num number(4));
insert into class values (1, 'CS', 999 );
insert into class values (1, 'MA', 111 );
insert into class values (1, 'DE', 222 );
insert into class values (2, 'CS', 999 );
insert into class values (2, 'MA', 111 );
insert into class values (2, 'DE', 222 );
insert into class values (3, 'CS', 999 );
insert into class values (4, 'CS', 999 );

输出：

  ID NAME
---- -----------
   2 John Doe

Answer 3

这个怎么样：

SELECT *
  FROM instructor i
 WHERE NOT EXISTS
          (SELECT *
             FROM class c
            WHERE c.instructor_id = i.human_id
           MINUS
           SELECT *
             FROM class c
            WHERE instructor_id = (SELECT human.id
                                     FROM human
                                    WHERE FIRST = 'Foo' AND LAST = 'Bar'));

Answer 4

我假设教师可以多次教授同一个班级（如果他们不能在某种程度上简化查询）。我还假设输入是作为“名字，姓氏”而不是直接作为human.id给出的，尽管这是一种运行查询的糟糕方式;如果多个教师具有相同的名字和姓氏怎么办？使用唯一标识符。

无论如何，这里是。可以对其进行修改以适应数据模型或输入模型的变化;现在它是基于OP所述的要求。

with sel(p_id) as (select id from human where first = 'foo' and last = 'bar'),
     a(i, ct)  as (select instructor_id, count(distinct class_code || class_num)
                   from class group by instructor_id)
select i from a join sel on i != p_id
where
(select count(distinct class_code || class_num) from class 
                         where instructor_id in (p_id, i)) =
(select min(ct) from a a1 where a1.i in (p_id, a.i));

SQL Query执行除法

4 个答案: