Question

StudentID   StudentID NO
1           111
1           211
1           111
2           444
2           444 
2           444
5           555
5           555
5           NULL
6           66
6           66
6           66
6           66

输出 1 5

输出为1和5，因为它们具有不同的studentIDnos wheareas 2和6具有相同的studentIDnos。我们也应该照顾无效。考虑5

我需要一个SQL server Query来获取此输出

Answer 1

你可以通过这样的group by和having子句实现这个目的：

SELECT studentID
FROM YourTable
GROUP BY studentID
HAVING count(distinct isnull(studentID_NO,1)) > 1

它将返回每个学生ID超过1的学生

Answer 2

INSERT INTO @Table1
    (StudentID, StudentIDNO)
VALUES
    (1, '111'),
    (1, '211'),
    (1, '111'),
    (2, '444'),
    (2, '444'),
    (2, '444'),
    (5, '555'),
    (5, '555'),
    (5, NULL),
    (6, '66'),
    (6, '66'),
    (6, '66'),
    (6, '66')
;

Select T.StudentID from (
select  StudentID, StudentIDNO from @Table1
GRoup by StudentID, StudentIDNO)T
GROUP BY T.StudentID
HAVING COUNT(T.StudentID) > 1

Answer 3

一种方式：

select StudentID from T
group by StudentID
having count(distinct isnull([StudentID NO], -1)) > 1

假设-1不会出现

在SQL Server中的相同表中查找MisMatch行

3 个答案: