[GENERAL] how to replace last 4 digital phone number into star using regexp_replace?

[sunpeng]

hi, friends,
   Our phone number format is 11 digital, i want to replace last 4 digital
into star, for example:
   Replace this string including 11 digital phone number:
   '18910180000,13910180000,232,abc'
    into:
     '1891018****,1391018****,232,abc'
   I try to use:
   select
regexp_replace('18910180000,13910180000,232,abc','[0-9]{7}(\d+)','****','g')
   But it doesn't work, it will return:
     "****,****,232,abc"
     Can anyone help me? Thanks a million!

Best Regards
peng