获取两个sql server行之间的区别 [英] Get difference between two sql server rows

问题描述

向大家致敬。



我的样式表格如下：

Salutation to you all.

I have my sq l table in the example format below:

id      Stud          Amount    Sem

2       007           5600      SemI
3       002           4500      Sem1 
4       001           5600      SemI
5       007           4500      Sem1I
6       001           5600      SemII
7       002           4500      Sem1
8       002           4500      Sem1I
9       005           4500      SemII

如何编写Sql查询以仅获得仅以semII付款且不以semI付款的学生。

Eg学生005



感谢您的支持



已添加代码块 - OriginalGriff [/ edit]

How can i write an Sql query to get only those students who have made payments in semII only and NOT in semI.
E.g. Student 005

Thanks for your support

[edit]Code block added - OriginalGriff[/edit]

推荐答案

SELECT t1.stud FROM table1 t1 WHERE  t1.sem='semII' AND  NOT EXISTS
(SELECT * FROM table1 t2 WHERE t2.sem='semI' AND t1.stud=t2.stud)

尝试：

Try:

SELECT Stud FROM MyTable a
JOIN (SELECT stud, COUNT(sem) AS sems
      FROM MyTable
      WHERE Sem='SemI' OR Sem='SemII'
      GROUP BY Stud) b
ON a.Stud = b.Stud
WHERE b.sems=1 AND a.Sem='SEMII'

你可以做到......借助于条件......



其中条件的使用方式与bool条件相同。例如

hi you can do it...with the help of where condition...

Where Condition is used like that a bool condition. for example is

select count(*) from TableName where columnname="Condition Value"

如果上述查询返回1则条件为真，其他条件为假。

试试这个

if the above query is return 1 then where condition is true other wise condition is false.
try this

Select * from Student where sem='SemII'

任何查询回复..

for any query hit to reply..

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