Separator and order by not supported in group_concat

[jackysp]

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

create table t1 (grp int, a bigint unsigned, c char(10) not null, d char(10) not null);
insert into t1 values (1,1,"a","a"); 
insert into t1 values (2,2,"b","a"); 
insert into t1 values (2,3,"c","b");
insert into t1 values (3,4,"E","a");
insert into t1 values (3,5,"C","b");
select grp,group_concat(c separator ",") from t1 group by grp;    
select grp,group_concat(c order by c) from t1 group by grp; 

2. What did you expect to see?

grp	group_concat(c separator ",")
1	a
2	b,c
3	E,C
grp	group_concat(c order by c)
1	a
2	b,c
3	C,E

3. What did you see instead?

ERROR 1105 (HY000) at line 7: line 0 column 35 near " ",") from t1 group by grp" (total length 61)

4. What version of TiDB are you using (tidb-server -V)?

[morgo]

Separator is now supported, order by is parse but ignored:

tidb> select grp,group_concat(c separator "#") from t1 group by grp;    
+------+-------------------------------+
| grp  | group_concat(c separator "#") |
+------+-------------------------------+
|    1 | a                             |
|    3 | E#C                           |
|    2 | b#c                           |
+------+-------------------------------+
3 rows in set (0.01 sec)

tidb> select grp,group_concat(c order by c) from t1 group by grp; 
+------+----------------------------+
| grp  | group_concat(c order by c) |
+------+----------------------------+
|    1 | a                          |
|    3 | E,C                        |
|    2 | b,c                        |
+------+----------------------------+
3 rows in set (0.00 sec)

[morgo]

ORDER BY is a duplicate of #6838

I am going to close this issue now, as the new issue better describes the remaining scope.