Transposing the data - QUERY - response (3) by ulrich

Are you looking for something like 

select ID, 
       change_id, 
       update_time,
       substr(max(case when columnname = 'change_col_1' then cast(update_time as char(30)) ||change_log_to else null end) over (partition by ID,change_id order by update_time, columnname rows between unbounded preceding and current row ),31) as last_val_col1,       
       substr(max(case when columnname = 'change_col_2' then cast(update_time as char(30)) ||change_log_to else null end) over (partition by ID,change_id order by update_time, columnname rows between unbounded preceding and current row ),31) as last_val_col2,       
       substr(max(case when columnname = 'change_col_3' then cast(update_time as char(30)) ||change_log_to else null end) over (partition by ID,change_id order by update_time, columnname rows between unbounded preceding and current row ),31) as last_val_col3,       
       substr(max(case when columnname = 'change_col_4' then cast(update_time as char(30)) ||change_log_to else null end) over (partition by ID,change_id order by update_time, columnname rows between unbounded preceding and current row ),31) as last_val_col4,      
       substr(max(case when columnname = 'change_col_5' then cast(update_time as char(30)) ||change_log_to else null end) over (partition by ID,change_id order by update_time, columnname rows between unbounded preceding and current row ),31) as last_val_col5      
from stage_tbl
qualify row_number() over (partition by id, change_id, update_time order by columnname desc ) = 1

Its not 100% as of your expected results but it is also unclear to me how
INSERT INTO expected_res VALUES (1234,5678,'2013-07-01 07:00.00.000000','erf','lks',NULL,'rfd','lop');
should be generated from your stg data...