Hi monks,

I'm puzzled by the behaviour of the following snippet of code:

my $query = 'apple';
my $sql = qq{ SELECT COUNT(*)
  FROM table1
  WHERE name=?
  UNION SELECT COUNT(*) FROM table2
  WHERE name=?
};

my $sth->execute($sql, $query, $query)
my $rows = $sth->fetchall_arrayref();

#table1
apple
apple
orange
pear

#table2
pear
apple
orange
orange

[download]
Given a query to count the number of rows containing 'apple' from the above SQL, $rows returns: 
$VAR1 = [ [ '2' ], [ '1' ] ];

[download]
That's correct. However, when the contents of the tables change as follows (1 more 'apple' added to table2): 
#table1
apple
apple
orange
pear

#table2
pear
apple
orange
orange
apple

[download]
That is, two instances of 'apple' in table1 and two in table2. In this case, $rows returns: 
$VAR1 = [ [ '2' ] ];

[download]
That is, a single annonymous array in an AoA.

I was expecting $VAR1 to contain: 

$VAR1 = [ [ '2' ], [ '2' ] ];

[download]
Could someone enlighten me on what's going there?

Thanks in anticipation :)

In reply to Perl DBI fetchall_arrayref - puzzling behaviour by kiat

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