(PHP 5 >= 5.1.0, PECL pdo:0.2-1.0.3)
PDO->query() — Executes an SQL statement, returning a result set as a PDOStatement object
PDO->query() executes an SQL statement in a single function call, returning the result set (if any) returned by the statement as a PDOStatement object.
For a query that you need to issue multiple times, you will realize better performance if you prepare a PDOStatement object using PDO->prepare() and issue the statement with multiple calls to PDOStatement->execute().
If you do not fetch all of the data in a result set before issuing your next call to PDO->query(), your call may fail. Call PDOStatement->closeCursor() to release the database resources associated with the PDOStatement object before issuing your next call to PDO->query().
Note: Although this function is only documented as having a single parameter, you may pass additional arguments to this function. They will be treated as though you called PDOStatement->setFetchMode() on the resultant statement object.
The SQL statement to prepare and execute.
PDO->query() returns a PDOStatement object.
Example#1 Demonstrate PDO::query
A nice feature of PDO->query() is that it enables you to iterate over the rowset returned by a successfully executed SELECT statement.
<?php
function getFruit($conn) {
$sql = 'SELECT name, colour, calories FROM fruit ORDER BY name';
foreach ($conn->query($sql) as $row) {
print $row['NAME'] . "\t";
print $row['COLOUR'] . "\t";
print $row['CALORIES'] . "\n";
}
}
?>
上例将输出：
apple red 150 banana yellow 250 kiwi brown 75 lemon yellow 25 orange orange 300 pear green 150 watermelon pink 90