PDO不会两次运行相同的查询？

Question

美好的一天!

我试图用相同的参数运行相同的更新语句两次,似乎它没有在第二种情况下执行:

$update_query = $this->db->connection->prepare('UPDATE `Table SET `field` = :price WHERE (`partnum` = :partnum)');

$update_query->execute(array('price' => 123, 'partnum' => test));
var_dump($update_query->rowCount()); //returns 1

// If I insert here any statement it works as expected

$update_query->execute(array('price' => 123, 'partnum' => test));
var_dump($update_query->rowCount()); //returns 0!

我没有启用mysql查询缓存.

谢谢!

Answer 1

如果UPDATE连续更改没有数据,MySQL则不会将此行计为受影响:

mysql> SELECT val FROM t_source2 WHERE id = 1;
+-----+
| val |
+-----+
|  10 |
+-----+
1 row in set (0.00 sec)

mysql> UPDATE t_source2 SET val = 1 WHERE id = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> UPDATE t_source2 SET val = 1 WHERE id = 1;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

第二个UPDATE语句确实执行但从影响MySQL的角度来看没有任何行,因为它没有改变任何内容.