How to change Custom field Type , single select to Multi select

[_Download2021]

Hi ,

I got a request , to change Custom field Type , single select to Multi select 

How to change , can any one guide me, is it possible or not 

[Dirk Ronsmans]

Hi @_Download2021 ,

Once a custom field is created you cannot change the type anymore.

Only way to do it would be to create a new field, migrate over any data if you have some and delete the old field.

Make sure to also validate any filters/dashboards/... that were created with the old field.

[Nic Brough -Adaptavist-]

On server/DC, you can actually do this, but it's a complete hack. 

If you have write access to the database, you can change the field type in the customfield table.  

If you're going to do that, you need to keep it minimal.  Stop Jira, take a full backup of the database, validate that you can use the backup to recreate a working Jira, then go and amend only the class name for the field in the database.  Do not amend anything else.  Restart Jira, then go to the custom field in the admin section and edit it. 

Change the searcher to the one you want to use.  You may find it has nothing set, and even if that is the right thing for you, select another one.  If it's set to the one you want, doesn't matter, change it to something else and save it.  In both cases, go straight back in and edit it again, changing it to the one you do want.

Now run a full locking re-index.

Note that this only works for certain conversions.  You can change url and short text fields to long text, or single-select to multi-select, or radio buttons to checkboxes, but you can't go back - you can't convert multi-select to single select for example.  And you can't convert incompatible field types - text to select, date, number, will just trash your field data.