如何分组工作！ [英] How group by works !

问题描述

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

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


COURSEID ------课程名称------ COURSEGROUP

PHY144 ------------物理------------------ A

PHY144 ------------物理------------------ B


我真正需要的是

COURSEID ------课程名称------ COURSEGROUP

PHY144 ----------物理学------------------ A，B


请帮助我

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


COURSEID-------COURSENAME------COURSEGROUP

PHY144----------physics------------------A

PHY144----------physics------------------B


What I really need is

COURSEID-------COURSENAME------COURSEGROUP

PHY144----------physics------------------A, B


please help me

推荐答案

您将必须编写一个子查询.您不能单独使用group by将其用逗号分隔.您可以在此处找到示例 http://stackoverflow.com/questions/7448734/sql-comma-separated-row-with-group-by-子句 [

You will have to write a sub query. You can not have a comma separated aggregate using group by alone. You can find an example here http://stackoverflow.com/questions/7448734/sql-comma-separated-row-with-group-by-clause[^]

hi，
试试这个，

try this,

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

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