You might use array of arrays for you data:

push @studentInfo, [@row];
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Then, $studentInfo[$x][0] contains the ID and $studentIfno[$x][1] the name. If the IDs are uniqe, you may profit from Perl's hashes, so build your structure in a different way:

my %studentInfo;
while (my @row = $sth_queryID->fetchrow){
   $studentInfo{$row[0]} = $row[1];
}
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In this case, $studentInfo{$id} contains the name (and should be renamed to %id_to_name or similar).
Update: see perldsc for details.