You were close.
# Create an anonymous arrayref
my $arrayref = [1,2,3];
# Create a reference to an existing array
my @array = (1,2,3);
my $arrayref2 = \@array;
# Get a single value from the arrayref:
my $one = $arrayref2->[0];
# Get all the values from the arrayref:
my ($one,$two,$three) = @$arrayref2;
In the code you posted you wrote:
[$sql_return]
Which is putting the arrayref provided by DBI inside another arrayref. Instead do this:
@$sql_return
It might help you visualize the data structure if you use
Data::Dumper, like this:
use Data::Dumper;
#...
my $sql_return = $sth_tss->fetchall_arrayref;
print Dumper $sql_return;