Oracle merges a column in the query results into a single string ____oracle

Select Max (Sys_connect_by_path (username, '; ') from
(
Select
U.username,rownum ro
From
T_base_user U,t_base_role_user ru
where
U.id = Ru.userid
) Newtab
Start with newtab.ro = 1
Connect by Prior newtab.ro = Newtab.ro-1

Note: T_base_user is a user table t_base_role_user is a role user relationship table

Sys_connect_by_path (column names to be merged, delimiters)

The results of the query are as follows:

                                John; Dick; Harry