选择 mysql 中具有相同值的行

Question

In a [KHS] table, some rows have the same value for the id_student and courses column. and i would like to choose higher "KE" column if they have id_student and courses column..

id_grade	id_student	courses	ke
1	2001	A	2
2	2001	A	1
3	2001	B	1
4	2002	A	2
5	2002	A	1

and expected result is:

id_grade	id_student	courses	ke
1	2001	A	2
3	2001	B	1
4	2002	A	2

What SQL statement should I use? Thanks in advance!

Answer 1

Try this:

select id_grade, id_student, courses, max(ke) ke
from temp
group by id_student, courses