Toppers wrote...
I don't think you can do it without code...
....

Well not if there could be more than a few dozen items to concatenate,
but if there were fewer items, no code required.

"sebastian stephenson" wrote:
I have set of data

Key Text
1 x
1 y
1 z
2 a
2 b
3 c
3 d

Would this always be sorted by Key? I'll assume so, and I'll also
assume the table above, excluding the top row of labels, is named Tbl.

I want to use a function that will return

Key Text
1 x,y,z
2 a,b
3 c,d
....

If the result range were in D1:E4 with labels in D1:E1, try these
formulas.

D2:
=INDEX(Tbl,1,1)

E2:
=INDEX(Tbl,1,2)&IF(COUNTIF(INDEX(Tbl,0,1),D2)1,", "&INDEX(Tbl,2,2),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D2)2,","&INDEX(Tbl,3,2 ),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D2)3,","&INDEX(Tbl,4,2 ),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D2)4,","&INDEX(Tbl,5,2 ),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D2)5,","&INDEX(Tbl,6,2 ),"")

D3:
=INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$2:D 2))+1,1)

E3:
=INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$2:D 2))+1,2)
&IF(COUNTIF(INDEX(Tbl,0,1),D3)1,
","&INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$ 2:D2))+2,2),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D3)2,
","&INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$ 2:D2))+3,2),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D3)3,
","&INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$ 2:D2))+4,2),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D3)4,
","&INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$ 2:D2))+5,2),"")
&IF(COUNTIF(INDEX(Tbl,0,1),D3)5,
","&INDEX(Tbl,SUMPRODUCT(COUNTIF(INDEX(Tbl,0,1),D$ 2:D2))+6,2),"")

Fill D3:E3 down as far as needed.

On the other hand, if one uses Laurent Longre's MOREFUNC.XLL add-in,
the column E formulas could be reduced to

E2 [array formula]:
=MID(MCONCAT(IF(INDEX(Tbl,0,1)=D2,","&INDEX(Tbl,0, 2),"")),2,255)

Fill E2 down as far as needed.