 <p>You probably want to use <a href="https://cloud.google.com/bigquery/query-reference#within" rel="nofollow">WITHIN</a> RECORD aggregation here, not GROUP BY</p> <pre><code> select concat(p1, '.', p2), Web_Address_ FROM (SELECT NTH(2,split(Web_Ad`enter code here`dress_,'.')) WITHIN RECORD p1, NTH(3,split(Web_Address_,'.')) WITHIN RECORD p2, Web_Address_ FROM (SELECT 'a.b.c' as Web_Address_)) </code></pre> <p>P.S. If you just trying to cut off first part of web address, it will be easier to do with RIGHT and INSTR functions.</p>