index=my_index (sourcetype=sourcetypeA OR sourcetype=sourcetypeB)
| rename ChangeUser AS ID
| stats values(CreateTime) AS CreateTime values(CreateUser) AS CreateUser values(ChangeTime) AS ChangeTime values(UserName) AS UserName BY ID
| fields - ID
| rename UserName AS ChangeUser
| table CreateTime CreateUser ChangeTime ChangeUser
If you have more fields to add, use the values(fields) AS field approach.
it seems doesn't work, the query values(fields) can only extract the value of fields, but can't show the relationship between two sourcetype, when the field ChangeUser is "2" , it must mapping to sourceB and find ID equal 2, and got the UserName=Jack=ChangeUser=2