如何在SQL中检查多个不相关的条件？

Question

我有以下查询：

SQL> SELECT DISTINCT INSTRUCTORADDRESSMODPER.instructor_id, Instructor.instructor_name, InstructorRank.salary, Student.specification_id
  2  FROM INSTRUCTORADDRESSMODPER
  3  JOIN Student ON INSTRUCTORADDRESSMODPER.student_id = Student.student_id
  4  JOIN Instructor ON INSTRUCTORADDRESSMODPER.instructor_id = Instructor.instructor_id
  5  JOIN InstructorRank ON Instructor.instructor_rank = InstructorRank.instructor_rank
  6  ORDER BY specification_id;

产生了以下结果：

我试图获得结果，该结果显示具有相同薪水和相同规格的讲师的列值与图中突出显示的相同。现在这两个条件需要完全不同的检查，我什至不知道如何开始。

Answer 1

您可以使用window函数count，如下所示：

Select * from 
(SELECT DISTINCT INSTRUCTORADDRESSMODPER.instructor_id, Instructor.instructor_name, InstructorRank.salary, Student.specification_id,
          Count(1) over (partition by InstructorRank.salary, Student.specification_id) as cnt
     FROM INSTRUCTORADDRESSMODPER
     JOIN Student ON INSTRUCTORADDRESSMODPER.student_id = Student.student_id
     JOIN Instructor ON INSTRUCTORADDRESSMODPER.instructor_id = Instructor.instructor_id
     JOIN InstructorRank ON Instructor.instructor_rank = InstructorRank.instructor_rank)
Where cnt > 1
ORDER BY specification_id;

Answer 2

您需要这样的东西吗？

SELECT instructor_id, instructor_name, instructor_name, specification_id
FROM (
SELECT DISTINCT INSTRUCTORADDRESSMODPER.instructor_id, Instructor.instructor_name, InstructorRank.instructor_name, Student.specification_id
, COUNT(distinct INSTRUCTORADDRESSMODPER.instructor_id)over(partition by InstructorRank.salary, Student.specification_id) cnt
  FROM INSTRUCTORADDRESSMODPER
  JOIN Student ON INSTRUCTORADDRESSMODPER.student_id = Student.student_id
  JOIN Instructor ON INSTRUCTORADDRESSMODPER.instructor_id = Instructor.instructor_id
  JOIN InstructorRank ON Instructor.instructor_rank = InstructorRank.instructor_rank
  ORDER BY specification_id
  )
WHERE cnt > 1
;

Answer 3

SQL> SELECT DISTINCT INSTRUCTORADDRESSMODPER.instructor_id, 
Instructor.instructor_name,InstructorRank.salary, Student.specification_id
FROM INSTRUCTORADDRESSMODPER
WHERE 1=1
AND INSTRUCTORADDRESSMODPER.student_id = Student.student_id
AND  INSTRUCTORADDRESSMODPER.instructor_id = Instructor.instructor_id
AND  Instructor.instructor_rank = InstructorRank.instructor_rank
AND ORDER BY specification_id
AND ...;

通过以上使用，可以添加需要的条件。

如何在SQL中检查多个不相关的条件？

How to check more than one unrelated conditions in SQL?

sql

oracle

oracle11g