oracle regexp output left hand side

-- substr(table_name,instr(table_name,'GLT')+1)

select distinct table_name from 
(
select 
case when table_name like '%GLT%'
    then substr(table_name,1,instr(table_name,'GLT')-2)
    else table_name
end as table_name
from 
(
select 
REGEXP_SUBSTR (trim(regexp_substr(t.tables_accessed, '[^,]+', 1, levels.column_value)) , '[^.]+', 1, 1) as owner ,
REGEXP_SUBSTR (trim(regexp_substr(t.tables_accessed, '[^,]+', 1, levels.column_value)) , '[^.]+', 1, 2) as table_name,
test_name,
test_type,
test_category,
test_notes
from 
(
select aa.*, cc.sqlid, bb.tables_accessed
from
(
select
    test_name,
    test_type,
    test_category,
    test_notes,
    end_snap,
    SUM(CASE WHEN name = 'secs - elapsed time' THEN round(delta,2) ELSE 0 END) elapsed,
    SUM(CASE WHEN name = 'secs - CPU used by this session' THEN round(delta,2) ELSE 0 END) cpu_used
from
(
    with q1 as (select *
                from gluent_app.get_run_stats
                where test_name in (select test_name from gluent_app.get_run_stats
                        where stat_class = 'tables accessed'
                        and name is not null and name not like 'SYS%' and name not like ' %'))
     select substr(test_name,1,40) test_name, test_type, test_category, test_notes, begin_snap, to_char(end_snap,'MM/DD/YY HH24:MI:SS') end_snap, stat_class, name, delta from
        (
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                'secs - ' || name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (snap_time - (lag(snap_time) over (order by snap_time)))*86400 delta,
                1 stat_order
            from q1
            where name = 'elapsed time'
        union all
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                'secs - ' || name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (value-lag(value) over (order by snap_time))/100 delta,
                2 stat_order
            from q1
            where name = 'CPU used by this session'
        union all
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (value-lag(value) over (order by snap_time)) delta,
                4 stat_order
            from q1
            where STAT_CLASS = 'sql_id'
        union all
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (value-lag(value) over (order by snap_time)) delta,
                5 stat_order
            from q1
            where STAT_CLASS = 'tables accessed'       )
        where snap_type = 'END'
        order by end_snap asc, test_name asc, stat_order asc, delta desc
)
group by test_name, test_type, test_category, test_notes, end_snap
order by test_type asc, end_snap asc
) aa,
(
select * from
(
select
    test_name,
    test_type,
    test_category,
    test_notes,
    end_snap,
    (CASE WHEN stat_class = 'tables accessed' THEN name END) tables_accessed
from
(
    with q1 as (select *
                from gluent_app.get_run_stats
                where test_name in (select test_name from gluent_app.get_run_stats
                        where stat_class = 'tables accessed'
                        and name is not null and name not like 'SYS%' and name not like ' %'))
     select substr(test_name,1,40) test_name, test_type, test_category, test_notes, begin_snap, to_char(end_snap,'MM/DD/YY HH24:MI:SS') end_snap, stat_class, name, delta from
        (
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (value-lag(value) over (order by snap_time)) delta,
                5 stat_order
            from q1
            where STAT_CLASS = 'tables accessed'       )
        where snap_type = 'END'
        order by end_snap asc, test_name asc, stat_order asc, delta desc
)
group by test_name, test_type, test_category, test_notes, end_snap,(CASE WHEN stat_class = 'tables accessed' THEN name END)
order by test_type asc, end_snap asc
)
where tables_accessed is not null) bb,
(
select * from
(
select
    test_name,
    test_type,
    test_category,
    test_notes,
    end_snap,
    (CASE WHEN stat_class = 'sql_id' THEN name END) sqlid
from
(
    with q1 as (select *
                from gluent_app.get_run_stats
                where test_name in (select test_name from gluent_app.get_run_stats
                        where stat_class = 'tables accessed'
                        and name is not null and name not like 'SYS%' and name not like ' %'))
     select substr(test_name,1,40) test_name, test_type, test_category, test_notes, begin_snap, to_char(end_snap,'MM/DD/YY HH24:MI:SS') end_snap, stat_class, name, delta from
        (
        select
                test_name, test_type, test_category, test_notes, snap_type, stat_class,
                name as name,
                lag(snap_time) over (order by snap_time) begin_snap,
                snap_time end_snap,
                (value-lag(value) over (order by snap_time)) delta,
                4 stat_order
            from q1
            where STAT_CLASS = 'sql_id'       )
        where snap_type = 'END'
        order by end_snap asc, test_name asc, stat_order asc, delta desc
)
group by test_name, test_type, test_category, test_notes, end_snap, (CASE WHEN stat_class = 'sql_id' THEN name END), (CASE WHEN stat_class = 'tables accessed' THEN name END)
order by test_type asc, end_snap asc
)
) cc
where aa.test_name = bb.test_name
and aa.test_name = cc.test_name
and aa.test_type = bb.test_type
and aa.test_type = cc.test_type
and aa.end_snap = bb.end_snap
and aa.end_snap = cc.end_snap
) t,
table(cast(multiset(select level from dual connect by  level <= length (regexp_replace(t.tables_accessed, '[^,]+'))  + 1) as sys.OdciNumberList)) levels
)
)
order by 1 asc
/