select *
from
xpath_table (
   'id',
   'data',
   '_comment',
   '/data/name',
   'path <@ ''0.1.57'''
   ) as t (author varchar);

 author 
--------
 71
 72
 73
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
...
 168
 169
 170
 171
(69 rows)

(END)