I want to have a custom record field, get data from related record field with out any aggregation it is a text field(like we have group_concat and group by in SQL)

This relationship is one to may

Do you have a specific question beyond what is covered in the documentation?

docs.appian.com/.../custom-record-fields.html

Thanks for response. Yes, Actually I am not able to access the related record in "Write your own expression" section. And in "Aggregate Related Records" section I am getting only count. I want values comma separated or semicolon separated 

Or if you have any other suggestion for applying the sorting on read only grid field having data from One to Many relationship related record. I am trying to get this field in mail record as I am getting error while applying sorting

Could you explain this use case in more detail? Sorting items in a grid does not require custom record fields typically.

Yes, I have a record lets say "Main_Record". This record has a relationship with another record lets say "Related_Record". I have created a readonly grid using "Main_Record". This grid has one column from "Related_Record as well. Like shown in below table column c data is from related record. This column as three rows (Its one to many relationship)

User wants this grid to be sorted by all columns.  First two column sorting is working fine by "SortField" properties of grid column. But as soon as I click on Third column I am getting error "Sorting can not be applied on one-to many relationship record field" 

So, now I want this third column to be a custom record field of "Main_Record" hoping that sorting will work as expected

Thanks for your attention

Yes, I have a record lets say "Main_Record". This record has a relationship with another record lets say "Related_Record". I have created a readonly grid using "Main_Record". This grid has one column from "Related_Record as well. Like shown in below table column c data is from related record. This column as three rows (Its one to many relationship)

User wants this grid to be sorted by all columns.  First two column sorting is working fine by "SortField" properties of grid column. But as soon as I click on Third column I am getting error "Sorting can not be applied on one-to many relationship record field" 

So, now I want this third column to be a custom record field of "Main_Record" hoping that sorting will work as expected

Thanks for your attention

OK. I did some testing and did not get this to work. A custom record field does also not support a "group_concat" like behaviour. At least I did not get it to work in the time I had.

So, if this requirement is a must-have, you could modify the process that adds/removes the sub record relationship in a way that it concats the values into a field in the main record.

Thank you Stefan, for your time and efforts. Now I have some confidence to talk to business if we can skip sorting of sub record fields. If not then I will try to modify the data source itself and have all columns in one record.