PDOStatement::columnCount

PHP PDO Reference Manual

PDOStatement::columnCount — Returns the number of columns in the result set. (PHP 5 >= 5.1.0, PECL pdo >= 0.2.0)

Description

Syntax

int PDOStatement::columnCount ( void )

PDOStatement::columnCount() returns the number of columns in the result set represented by the PDOStatement object.

If the PDOStatement object was returned by PDO::query(), the column count is immediately available.

If the PDOStatement object was returned by PDO::prepare(), the column count cannot be accurately calculated until PDOStatement::execute() is called.

Return Values

Returns the number of columns in the result set represented by the PDOStatement object. If there is no result set, PDOStatement::columnCount() returns 0.

Examples

Count columns

The following example demonstrates how to use PDOStatement::columnCount() with a result set and an empty set.

<?php
$dbh = new PDO('odbc:sample', 'db2inst1', 'ibmdb2');

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

/*  计算一个（不存在）的结果集中的列数 */
$colcount = $sth->columnCount();
print("Before execute(), result set has $colcount columns (should be 0)\n");

$sth->execute();

/* 计算结果集中的列数 */
$colcount = $sth->columnCount();
print("After execute(), result set has $colcount columns (should be 2)\n");

?>

The above example will output:

Before execute(), result set has 0 columns (should be 0)
After execute(), result set has 2 columns (should be 2)

PHP PDO Reference Manual