MySQL in a Nutshell, 2nd Edition

Name

selectcol_arrayref()

Synopsis

$dbh->selectcol_arrayref($sql_statement[, \%attri][, @bind_values])

This returns a reference to an array containing a value in the first column of each row selected. The SQL statement is given as the first argument of the function. This can be particularly useful if the first column is a key field. This function performs prepare() and execute() on the SQL statement. Here is an example:

...
my $sql_stmnt = "SELECT * FROM books";

my $book = $dbh->selectcol_arrayref($sql_stmnt);

foreach my $author_id (@$book){
   print "$author_id \n";
}

The prepare() method isn’t called to create a statement handle if the SQL statement is given with this method, making finish() unnecessary. However, a statement handle could be given instead. Since the result is an array reference, it must be deferenced to extract the data (i.e., @$book). Using foreach, each element of the array is extracted, one element per row of the results set, and the value of each temporarily stored in a variable here ($author_id, the first column of the table).