Iron clad?

-- prepare test data

declare @test-2 table (t varchar(50))

insert @test-2

select 'ov1' union all

select 'ov2' union all

select 'ov4' union all

select 'ov31' union all

select 'ssss1' union all

select 'ssss99'

-- show data before inserting new values

select * from @test-2

-- do the work

declare @prefix varchar(50)

select @prefix = 'ov' -- Throw anything in!

insert @test-2

select@prefix + convert(varchar, t.n + 1)

from(

selectmax(convert(int, substring(t, 1 + len(@prefix), 50))) n

from@test-2

wheret like @prefix + '%'

and not substring(t, 1 + len(@prefix), 50) like '%[^0-9]%'

) t

wherenot @prefix like '%[0-9]%'

and not t.n like '%[^0-9]%'

-- show data after inserting new values

select * from @test-2