PDOStatement::fetchColumn

(PHP 5 >= 5.1.0, PECL pdo >= 0.9.0)

PDOStatement::fetchColumn — Returns a single column from the next row of a result set

说明

string PDOStatement::fetchColumn ([ int $column_number = 0 ] )

Returns a single column from the next row of a result set or FALSE if there are no more rows.

参数

column_number: 0-indexed number of the column you wish to retrieve from the row. If no value is supplied, PDOStatement::fetchColumn() fetches the first column.

返回值

PDOStatement::fetchColumn() returns a single column in the next row of a result set.

Warning

There is no way to return another column from the same row if you use PDOStatement::fetchColumn() to retrieve data.

范例

Example #1 Return first column of the next row


<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();

/* Fetch the first column from the next row in the result set */
print("Fetch the first column from the next row in the result set:\n");
$result = $sth->fetchColumn();
print("name = $result\n");

print("Fetch the second column from the next row in the result set:\n");
$result = $sth->fetchColumn(1);
print("colour = $result\n");
?>

以上例程会输出：

Fetch the first column from the next row in the result set:
name = lemon
Fetch the second column from the next row in the result set:
colour = red

参见

PDO::query() - Executes an SQL statement, returning a result set as a PDOStatement object
PDOStatement::fetch() - Fetches the next row from a result set
PDOStatement::fetchAll() - Returns an array containing all of the result set rows
PDO::prepare() - Prepares a statement for execution and returns a statement object
PDOStatement::setFetchMode() - Set the default fetch mode for this statement

PHP手册 - N: Returns a single column from the next row of a result set

用户评论:

Nathan Pohpam (21-Mar-2012 10:49)

WARNING: PhoenixSegovia isn't quite correct. Perhaps it's implementation-dependent, but fetchColumn returns the empty string in my program. Beware!

PhoneixSegovia at GOOGLE_MAIL_SERVER dot com (21-Oct-2010 10:13)

fetchColumn return boolean false when a row not is found or don't had more rows.

seanferd at assmasterdonkeyranch dot com (25-Jan-2007 11:04)

This is an excellent method for returning a column count. For example: <?php $db = new PDO('mysql:host=localhost;dbname=pictures','user','password'); $pics = $db->query('SELECT COUNT(id) FROM pics'); $this->totalpics = $pics->fetchColumn(); $db = null; ?> In my case $pics->fetchColumn() returns 641 because that is how many pictures I have in my db.