Check name field with RegEx

Question

Hi,
Regular Expression is something new to me, and I understand it in it's basic explanation form.
Anyways, I have a table with a first name column, and a last name column.
The table has over a million records, anyways, I started to do something, but then I got confused.
select name_first from schema.table
where REGEXP_LIKE(name_first, [a-zA-Z]*);
So what I wanted to do is scan the name first, and name last to make sure that only legal characters were used, there should be no spaces, no numbers, and no other crazy stuff, so I would like to do a Select Statement and return anything that looks weird and if nothing weird matches, do nothing.
Any help would be appreciated.
Thanks

Answer 1

The query you were using is not correct. It will not return any row because it basically say find any string that don't have a-z and A-Z anywhere in it.
Example,
TEST@rman> l
  1   with t as (select 'ttt' val from dual
  2  union all select '%6gg' val  from dual
  3  union all select 'thisD' val from dual
  4  union all select 'L*;' val  from dual
  5  )
  6  select * from t
  7* where not REGEXP_LIKE(val,'[a-zA-Z]*')
TEST@rman> /
no rows selected
-- The correct one is
  1   with t as (select 'ttt' val from dual
  2  union all select '%6gg' val  from dual
  3  union all select 'thisD' val from dual
  4  union all select 'L*;' val  from dual
  5  )
  6  select * from t
  7* where not REGEXP_LIKE(val,'^[a-zA-Z]*$')
TEST@rman> /
VAL
%6gg
L*;
Or
  1   with t as (select 'ttt' val from dual
  2  union all select '%6gg' val  from dual
  3  union all select 'thisD' val from dual
  4  union all select 'L*;' val  from dual
  5  )
  6  select * from t
  7* where not REGEXP_LIKE(val,'^[[:alpha:]]*$')
TEST@rman> /
VAL
%6gg
L*;