I'll leave it to others to comment about using other modules to write csv files so proper quoting is performed and just discuss your imediate question

This is untested, demonstration code

use strict; 
use warnings; 
use DBI; 

my @clumps=(
            {table=>'tb1',file=>"csvfile1.csv"},
            {table=>'tb2',file=>"csvfile2.csv"},
            {table=>'tb3',file=>"csvfile3.csv"}
           );

my $dbname='a'; 
my $user='b';

# DBI CONNECTION
my($dbh) = DBI->connect("dbi:Ingres:$dbname","$user","")
or die "Could not connect to database $dbname\n";

for my $clump (@clumps){ 
  my ($sth) = $dbh->prepare('SELECT * FROM '.$clump->{table})
    or die "Prepare failed: $DBI::errstr\n";

  $sth->execute()
    or die "Prepare failed: $DBI::errstr\n";

  open my $fh, ">raw", $clump->{file} or die $clump->{file}. ": $!";
  $fh->print (join(",", @{$sth->{NAME}}), "\n"); #show header
  while (my @row = $sth->fetchrow_array())  
        {
            $fh->print (join(",", @row), "\n");
        };
  close $fh or die $clump->{file}.": $!";
    
  $sth->finish();
}
    
$dbh->disconnect();
[download]

Edit: Hippo was right "You've set @clumps as an arrayref but then treat as an array. Typo?"

he saw it as

my @clumps=[
            {table=>'tb1',file=>"csvfile1.csv"},
            {table=>'tb2',file=>"csvfile2.csv"},
            {table=>'tb3',file=>"csvfile3.csv"}
           ];
[download]