使用pdo关联查询mysql数据

try {

$pdo = new PDO('mysql:host=localhost;dbname=test;', 'root', '123456');

// 0.等值联结

$sql = 'SELECT c.name, o.id, o.customer_id, o.price FROM orders o, customer c WHERE o.customer_id = c.id AND c.name = :name';

// 1.内联结(与上面等值联结返回的查询结果相同)

// $sql = 'SELECT c.name, o.id, o.customer_id, o.price FROM orders o INNER JOIN customer c ON o.customer_id = c.id AND c.name=:name';

// (与内联结相比，外联结还包括没有相关联的行)

// 2.左外联结(这里联结orders，包括orders没有关联的行 o.price)

// $sql = 'SELECT c.id, o.price FROM orders o LEFT OUTER JOIN customer c ON o.customer_id = c.id AND c.name=:name';

// 3.右外联结(这里联结customer，包括customer没有关联的行 c.id)

// $sql = 'SELECT c.id, o.price FROM orders o RIGHT OUTER JOIN customer c ON o.customer_id = c.id AND c.name=:name';

// 4.另外还有自联结(self-join，自联结和子查询返回结果一样，但是一般比子查询快)

// 5.自然联结(natural-join)

$stmt = $pdo->prepare($sql);

//$stmt->bindValue(1, 'zhangsan');

//$stmt->bindParam(1, $name);

$name = 'zhangsan';

$stmt->execute(array(':name' => 'zhangsan'));

while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {

var_dump($row);

}

} catch (PDOException $e) {

echo $e->getMessage();

}

附上几个操作图

1.customer和orders表.png

2.等值联结查询.png

3.内联结查询.png

4.左外联结查询.png

5.右外联结查询.png