Question

I am new to Perl, and I am writing a script to fetch some rows from a database:

my @rows = $conn->fetchrow_array(1,2,3);

the result will be three rows of single column.

12345
56789
12376

How should I join them together as 12345,56789,56789

I tried,

my $list = join ",", @rows. 

Result: ARRAY(0x14f6de0),ARRAY(0x1508a90),ARRAY(0x15014c0)

Going through a foreach loop just print the results with a new line:

12345
56789
12376

What am I doing wrong ? have I got the concept of fetchrow_array wrong?

Answer 1

Each row is a reference to an array (because each row could contain multiple columns). Something like the following should work.

#!/usr/bin/perl

use strict; use warnings;

my @rows = (
    [ 12345 ],
    [ 56789 ],
    [ 12376 ],
);

my @vals = map @$_, @rows;

print join(',', @vals), "\n";

However, you are better off using selectcol_arrayref:

This utility method combines “prepare”, “execute”, and fetching one column from all the rows, into a single call. It returns a reference to an array containing the values of the first column from each row.