PDO::query
(PHP 5 >= 5.1.0, PECL pdo >= 0.2.0)
PDO::query — Executes an SQL statement, returning a result set as a PDOStatement object
说明
public PDOStatement PDO::query
( string $statement
)
public PDOStatement PDO::query
( string $statement
, int $PDO::FETCH_COLUMN
, int $colno
)
public PDOStatement PDO::query
( string $statement
, int $PDO::FETCH_CLASS
, string $classname
, array $ctorargs
)
public PDOStatement PDO::query
( string $statement
, int $PDO::FETCH_INTO
, object $object
)
PDO::query() executes an SQL statement in a single function call, returning the result set (if any) returned by the statement as a PDOStatement object.
For a query that you need to issue multiple times, you will realize better performance if you prepare a PDOStatement object using PDO::prepare() and issue the statement with multiple calls to PDOStatement::execute().
If you do not fetch all of the data in a result set before issuing your next call to PDO::query(), your call may fail. Call PDOStatement::closeCursor() to release the database resources associated with the PDOStatement object before issuing your next call to PDO::query().
Note:
Although this function is only documented as having a single parameter, you may pass additional arguments to this function. They will be treated as though you called PDOStatement::setFetchMode() on the resultant statement object.
参数
statement
The SQL statement to prepare and execute.
Data inside the query should be properly escaped.
返回值
PDO::query() returns a PDOStatement object, or FALSE
on failure.
范例
Example #1 Demonstrate PDO::query
A nice feature of PDO::query() is that it enables you to iterate over the rowset returned by a successfully executed SELECT statement.
<?php
function getFruit($conn) {
$sql = 'SELECT name, color, calories FROM fruit ORDER BY name';
foreach ($conn->query($sql) as $row) {
print $row['name'] . "t";
print $row['color'] . "t";
print $row['calories'] . "n";
}
}
?>
以上例程会输出：
apple red 150 banana yellow 250 kiwi brown 75 lemon yellow 25 orange orange 300 pear green 150 watermelon pink 90
参见
PDO::exec() - 执行一条 SQL 语句，并返回受影响的行数 PDO::prepare() - Prepares a statement for execution and returns a statement object PDOStatement::execute() - 执行一条预处理语句