为什么group by不起作用！ [英] why group by doesn't wrok!

问题描述

SELECT STUDENTID, COURSEID, COURSENAME, COURSEGROUP
FROM SOME_VIEW
WHERE STUDENTID=:STU_ID
--GROUP BY STUDENTID, COURSEID, COURSENAME
ORDER BY STUDENTID

我希望前面的代码像下面的
一样工作 如果我们有2个数据行

学生ID COURSEID COURSENAME COURSEGROUP
15 PHY144

I want the previous code to work like the following
if we have 2 data Rows

STUDENTID COURSEID COURSENAME COURSEGROUP
15 PHY144

推荐答案

您的问题还不清楚.我认为您需要做的是，

Your question is not exactly clear. I think what you need to do is,

SELECT DISTINCT STUDENTID, COURSEID, COURSENAME, COURSEGROUP
FROM   SOME_VIEW
WHERE  STUDENTID = :STID

试试这个，

SELECT STUDENTID，COURSEID，COURSENAME，COURSEGROUP
来自SOME_VIEW
GROUP BY STUDENTID，COURSEID，COURSENAME
具有STUDENTID = STU_ID

try this,

SELECT STUDENTID, COURSEID, COURSENAME, COURSEGROUP
FROM SOME_VIEW
GROUP BY STUDENTID, COURSEID, COURSENAME
HAVING STUDENTID=STU_ID

这篇关于为什么group by不起作用！的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！