You want that the searchA and searchB return a single line per field1, otherwise the join between the 2 lists will be wrong.
An example with a join between a list of users and the logins per server can be :
index=users username=* email=*
| stats values(email) AS email by username
| JOIN username
[
search index=servers login username=*
| stats values(host) AS server_login_list earliest(_time) AS recent_login earliest(host) AS recent_server by username
]
| table username email server_login_list recent_login recent_server
... View more