Question

查询我必须得到老师和学生ID

Select lk.teacherID,lk.studentID from Teacher a inner join student b 
on a.classkey = b.classkey

Teacher ID   Student ID
123            678
123            876
123            987
456            459
456            789

结束我正在寻找的结果： - 从两列

中查找SQL中的唯一ID

Unique IDs
123
678
876
987
456
459
789

Answer 1

这是你想要的吗？

select t.teacherId
from teachers t
union
select s.studentId
from students s;

编辑：

澄清一下，只需使用cross apply：

Select distinct id
from Teacher t inner join
     student s
     on t.classkey = s.classkey cross apply
     (values (t.teacherId), (s.studentId)) v(id);

Answer 2

Select lk.teacherID as UniqueIDs 
From(
Select lk.teacherID,lk.studentID from Teacher a inner join student b 
on a.classkey = b.classkey)a
GROUP By teacherID

Union all

Select lk.studentID as UniqueIDs From(
Select lk.teacherID,lk.studentID from Teacher a inner join student b 
on a.classkey = b.classkey)a
GROUP By studentID

Answer 3

不需要对数据进行多次传递。

如果OBJECT_ID（'tempdb ..＃temp'，'U'）不是NULL DROP TABLE #temp;

CREATE TABLE #temp (
    Teacher_ID int NOT NULL,
    Student_ID INT NOT NULL 
    );
INSERT #temp (Teacher_ID, Student_ID) VALUES 
    (123, 678),
    (123, 876),
    (123, 987),
    (456, 459),
    (456, 789);

--======================================

SELECT DISTINCT 
    UniqueID = x.ID
FROM 
    #temp t
    CROSS APPLY ( VALUES (t.Teacher_ID), (t.Student_ID) ) x (ID);

HTH，杰森

从两列中查找SQL中的唯一ID

3 个答案: