combine dupplicate lines that have only one different column

[hn.exvivo]

Hello everyone , i m beginner in jasper report  i have mysql table that have dupplicate row with one different columns i need to eliminate this dupplication in jasper report and combine this rows . Like this 

ColA	Col B	Col C	Col D
1	a	ab	k
1	a	cd	k
1	a	ef	k
2	b	za	l
2	b	ml	l
2	b	sq	l
2	b	aa	l
2	b	lk	l
3	c	qsq	m

 I need it to be like this 

Col A	Col B	Col C	Col D
1	a	ab cd ef	k
2	b	za ml sq aa lk	l
3	c	qsq	m

 How i can do it ? any help please