How to fetch last character and increment it in sql -

i have following query

  select case             when right('bpuren_3',1) '[a-z]'              concat('bpuren','_1')             else                concat('bpuren_3',right('bpuren_3',1)+1)               end 

i want output bpuren_4 getting result bpuren_34

select case     when right('bpuren_3',1) '[a-z]' 'bpuren_1'     else concat(left('bpuren_3', 7),right('bpuren_3',1)+1)     end 

no need concat('bpuren','_1') 'bpuren_1'

you change left('bpuren_3', 7) left('bpuren_3', len('bpuren_3') - 1) if 'bpuren_3' change in length (for example if parameter in real code)