Match the end half of an expersion to only letters SQL ORACLE

Question

I've got a column of data in an SQL table and after a first pass it contains only data starting with 'BVH' and 'BVG'. I want it to only contain data that has 3 numeric characters after this and no more letters. I have tried

OUC not like 'BVG%[a-z]%' and OUC not like 'BVH%[a-z]%'

as I don't know if the letters are going to fall in the first, second or third (or multiple) positions following the first 3 letters. I also can't know exactly what letters are going to appear

Example data

    BVH122
    BVH174
    BVH336
    BVH123
    BVH447
    BVH447
    BVH321
    BVH573
    BVG1NS
    BVG1T2
    BVH283
    BVH172
    BVG12T
    BVG1T2

Answer 1

Is that what you need?

with dat as (select 'BVH122' a from dual
   union all select 'BVH174' a from dual
   union all select 'BVG1NS' a from dual
   union all select 'BVH172' a from dual
   union all select 'BVG12T' a from dual
)
select * from dat where regexp_like(a,'[A-Z]{3}[0-9]{3}');

So your query is:

select * from table where regexp_like(OUC,'BV[GH]{1}[0-9]{3}');