Question

当我尝试发送以下查询时：

SET @attempts=0; 
SELECT mt1.TimeStamp, mt1.ReadAttempts - @attempts AS delta, 
       @attempts := mt1.ReadAttempts ReadAttempts 
FROM OneWireStats mt1 
WHERE SensorIndex=1 ORDER BY mt1.TimeStamp;

在表OneWireStats中的行之间获取增量值我收到以下错误：

查询失败并显示错误：您的SQL语法出错;校验与您的MySQL服务器版本对应的手册在'SELECT mt1.TimeStamp，mt1.ReadAttempts - @attempts附近使用的语法 AS delta，@ attempts：= mt1.Re'在第1行查询= SET @ attempts = 0; SELECT mt1.TimeStamp，mt1.ReadAttempts - @attempts AS delta，@ attempts ：= mt1.ReadAttempts ReadAttempts FROM OneWireStats mt1 WHERE SensorIndex = 1 ORDER BY mt1.TimeStamp;，查询号码：0

当我将上面的错误打印输出中的查询粘贴到mysql客户端时，它可以正常工作。

mysql>  SET @attempts=0; SELECT mt1.TimeStamp, mt1.ReadAttempts - @attempts AS delta, @attempts := mt1.ReadAttempts ReadAttempts FROM OneWireStats mt1 WHERE SensorIndex=1 ORDER BY mt1.TimeStamp LIMIT 10; Query OK, 0 rows affected (0.01 sec)

+---------------------+-------+--------------+ 
| TimeStamp           | delta | ReadAttempts |
+---------------------+-------+--------------+ 
| 2013-12-23 07:55:01 |  5532 |         5532 | 
| 2013-12-23 08:00:00 |   302 |         5834 | 
| 2013-12-23 08:05:01 |   302 |         6136 | 
| 2013-12-23 08:10:00 |   302 |         6438 | 
| 2013-12-23 08:15:00 |   302 |         6740 | 
| 2013-12-23 08:20:01 |   302 |         7042 | 
| 2013-12-23 08:25:00 |   302 |         7344 | 
| 2013-12-23 08:30:01 |   302 |         7646 | 
| 2013-12-23 08:35:00 |   302 |         7948 | 
| 2013-12-23 08:40:01 |   302 |         8250 |
+---------------------+-------+--------------+ 
10 rows in set (0.07 sec)

我使用以下php代码：

$query = mysql_real_escape_string(trim($queryobj[$counter]));

$sqlresult = mysql_query($query) or die("Query failed with error: ".mysql_error() . 
             " Query = " . $query . ", Query no: " . $counter);

我的查询中没有使用任何单引号或双引号，因此我还不了解错误打印输出。

很有提示。

Answer 1

您需要单独运行每个查询，可能像

mysql_query( "SET @attempts=0" );
mysql_query( "SELECT mt1.TimeStamp, mt1.ReadAttempts - @attempts AS delta, @attempts := mt1.ReadAttempts ReadAttempts FROM OneWireStats mt1 WHERE SensorIndex=1 ORDER BY mt1.TimeStamp" );

或使用mysqli的multi_query()，例如：

$query  = "SET @attempts=0;";
$query .= "SELECT mt1.TimeStamp, mt1.ReadAttempts - @attempts AS delta, @attempts := mt1.ReadAttempts ReadAttempts FROM OneWireStats mt1 WHERE SensorIndex=1 ORDER BY mt1.TimeStamp";
mysqli_multi_query($connection, $query);
mysqli_next_result($connection);
if ($result = mysqli_store_result($connection)) {
  //while loop here
}

mysql_query在sql语法中说错误，但同样的查询在mysql客户端中工作正常

1 个答案: