Re: Re: Re: Re: Re: MySQL / Perl Question

[chromatic]

SELECT COUNT(*) returns a single value. fetchrow_array returns an array. If you put the two together, you'll get the row count returned in a single-element array. Here's the correct example:

my @array  = (42);
my $count  = @array;
my ($elem) = @array;
print "$count element, which is ($elem)\n";

Update: Oops, it does return a list. The specification even says that it returns the value of the first field in scalar context (a little wantarray action). I'd have missed the boat completely if it didn't go on to warn about calling it in scalar context, though I didn't read that initially.

Hey everyone, look over there => !

[blakem]

Actually, fetchrow_array returns a list not an array. It makes a big difference in this discussion. Consider the following code:

#!/usr/bin/perl -wT
use strict;

my @array       = (42);

my $array_count = @array;     # array in scalar context
my $list_count  = (42);       # list in scalar context
my $sub_count   = testsub();  # list or array????

print "Array in scalar context:   $array_count\n",
      "List in scalar context:    $list_count\n",
      "Subs rv in scalar context: $sub_count\n";

sub testsub {
  # does this return a list or an array????
  return (42);
}

=OUTPUT
Array in scalar context:   1
List in scalar context:    42
Subs rv in scalar context: 42

The array evaluates to its number of elements, but the list evaluates to its rightmost member - in this case 42. The return value from the subroutine is actually a list not an array, which explains why $sub_count == $list_count == 42.

-Blake