fetchColumn return boolean false when a row not is found or don't had more rows.
PDOStatement::fetchColumn
(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.9.0)
PDOStatement::fetchColumn — Returns a single column from the next row of a result set
Description
Returns a single column from the next row of a result set or false if
there are no more rows.
Note:
PDOStatement::fetchColumn() should not be used to retrieve boolean columns, as it is impossible to distinguish a value of
falsefrom there being no more rows to retrieve. Use PDOStatement::fetch() instead.
Parameters
-
column -
0-indexed number of the column you wish to retrieve from the row. If no value is supplied, PDOStatement::fetchColumn() fetches the first column.
Return Values
PDOStatement::fetchColumn() returns a single column
from the next row of a result set or false if there are no more rows.
Warning
There is no way to return another column from the same row if you use PDOStatement::fetchColumn() to retrieve data.
Errors/Exceptions
Emits an error with level E_WARNING if the attribute PDO::ATTR_ERRMODE is set
to PDO::ERRMODE_WARNING.
Throws a PDOException if the attribute PDO::ATTR_ERRMODE
is set to PDO::ERRMODE_EXCEPTION.
Examples
Example #1 Return first column of the next row
<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();
print "Fetch the first column from the first row in the result set:\n";
$result = $sth->fetchColumn();
print "name = $result\n";
print "Fetch the second column from the second row in the result set:\n";
$result = $sth->fetchColumn(1);
print "colour = $result\n";
?>The above example will output:
Fetch the first column from the first row in the result set: name = lemon Fetch the second column from the second row in the result set: colour = red
See Also
- PDO::query() - Prepares and executes an SQL statement without placeholders
- PDOStatement::fetch() - Fetches the next row from a result set
- PDOStatement::fetchAll() - Fetches the remaining rows from a result set
- PDO::prepare() - Prepares a statement for execution and returns a statement object
- PDOStatement::setFetchMode() - Set the default fetch mode for this statement
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User Contributed Notes 3 notes
PhoneixSegovia at GOOGLE_MAIL_SERVER dot com ¶
14 years ago
seanferd at assmasterdonkeyranch dot com ¶
17 years ago
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.
theking2(at)king.ma ¶
11 months ago
When migrating from mysqli it is important that while mysqli_result::fetch_column will iterate over subsequent rows PDOStatement::fetchColumn will NOT!
<?php
while ( $row0 = $db->query("SELECT `value` FROM `bool`")->fetchColumn(0) ) {
var_dump( $row0 );
}
?>
is an endless loop unless the first column in the first row of the table bool is "0".
