Combine duplicate rows in column as comma separated values - Google Query - google-sheets

Question

If i have 2 columns viz., ID & Name, ID column containing duplicates, and if i want to group by ID to get unique ID's but name column should be a comma-separated list, can this be possible in Google Query?
| ID | Name |
===============
| 1001 | abc |
---------------
| 1001 | def |
---------------
| 1002 | kjg |
---------------
| 1003 | aof |
---------------
| 1003 | lmi |
---------------
| 1004 | xyz |
---------------
into
| ID | Name |
====================
| 1001 | abc, def |
--------------------
| 1002 | kjg |
--------------------
| 1003 | aof, lmi |
--------------------
| 1004 | xyz |
--------------------

Answer 1

try:
=ARRAYFORMULA({QUERY(QUERY({A2:B, B2:B},
"select Col1,max(Col2)
where Col1 is not null
group by Col1
pivot Col3"),
"select Col1
offset 1", 0), REGEXREPLACE(TRIM(
TRANSPOSE(QUERY(TRANSPOSE(QUERY(QUERY({A2:B&",", B2:B},
"select max(Col2)
where Col1 is not null
and Col2 <> ','
group by Col1
pivot Col3"),
"offset 1", 0)),,999^9))), ",$", )})
however, this may not work for massive datasets due to TRIM (which is needed to remove empty spaces) and REGEXREPLACE (which is needed to remove the end comma) limitations. otherwise, without it, the formula can handle anything:
=ARRAYFORMULA({QUERY(QUERY({A2:B, B2:B},
"select Col1,max(Col2)
where Col1 is not null
group by Col1
pivot Col3"),
"select Col1
offset 1", 0),
TRANSPOSE(QUERY(TRANSPOSE(QUERY(QUERY({A2:B&",", B2:B},
"select max(Col2)
where Col1 is not null
and Col2 <> ','
group by Col1
pivot Col3"),
"offset 1", 0)),,999^9))})

Answer 2

I looked through Query specification. I could not find a solution. So I made some formulas that do the job (because I found this task interesting).
D2 contains =unique(a2:a)
E2 contains =join(", ",transpose(filter($B$2:$B,$A$2:$A=D2)))and it's copied down.
I had to copy formulas down (far from beautiful formula)
Hope you find it helpful.
Reference
UNIQUE
JOIN
TRANSPOSE
FILTER

Answer 3

Here is an answer using QUERY.
=ARRAYFORMULA(REGEXREPLACE(TRIM(SPLIT(TRANSPOSE(SPLIT(
CONCATENATE(TRANSPOSE(QUERY({"♦"&A2:A&"♠", B2:B&", "},
"select max(Col2) where Col2 is not null group by Col2 pivot Col1", 0))),
"♦")), "♠")), ",$", ))
This comes directly from this question.
Player0 has answers with just amazing formulas that are able to reorganise data in a huge variety of ways.

Answer 4

if you could live with the end-comma present in the output you can try:
=ARRAYFORMULA({QUERY(QUERY({A2:B, B2:B},
"select Col1,max(Col3)
where Col1 is not null
and Col3 <> ','
group by Col1
pivot Col2"),
"select Col1 offset 1", 0),
TRANSPOSE(QUERY(TRANSPOSE(IFERROR(VLOOKUP(QUERY(QUERY({A2:B, B2:B},
"select Col1,max(Col3)
where Col1 is not null
and Col3 <> ','
group by Col1
pivot Col2"),
"select Col1 offset 1", 0),
QUERY(QUERY({A2:B, B2:B&","},
"select Col1,max(Col3)
where Col1 is not null
and Col3 <> ','
group by Col1
pivot Col2"),
"offset 1", 0),
SPLIT(TRANSPOSE(QUERY(TRANSPOSE(IF(QUERY(QUERY({A2:B, B2:B&","},
"select max(Col3)
where Col1 is not null
and Col3 <> ','
group by Col1
pivot Col2"),
"offset 1", 0)="",,COLUMN(B2:XXX)&",")),,999^99)), ","), 0))),,999^99))})
(tho this was never tested on an ultra-massive dataset but in theory, it should handle anything too)