MySQL查询在命令行中运行良好，但在运行时出现错误php

Question

我的查询在我的Linux服务器命令行上运行时运行正常，但当我尝试通过php执行时，它会引发php错误。

SELECT h.timestamp, d.valueparam, r.label, r.dataUnit 
FROM EventData d, EventHeader h, EventKeyReference r 
WHERE h.id = d.eventHeader_id AND h.serialNumber=$serialnumber 
AND d.keyParam='G002' AND r.EventKey = 'G002' 
ORDER BY h.timestamp DESC LIMIT 1; 

它给我这个错误：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AND d.keyParam='G002' AND r.EventKey = 'G002' ORDER BY h.timestamp DESC LIMIT 1' at line 1

有谁知道什么是错？

Answer 1

我的猜测：$serialnumber是空的，你的查询是：

SELECT h.timestamp, d.valueparam, r.label, r.dataUnit 
FROM EventData d, EventHeader h, EventKeyReference r 
WHERE h.id = d.eventHeader_id AND h.serialNumber= 
               // ^-- error here 
AND d.keyParam='G002' AND r.EventKey = 'G002' 
ORDER BY h.timestamp DESC LIMIT 1; 

Answer 2

更新查询如下，它会更加SERIALNUMBER是空

$sql = "SELECT h.timestamp, d.valueparam, r.label, r.dataUnit 
FROM EventData d, EventHeader h, EventKeyReference r 
WHERE h.id = d.eventHeader_id AND h.serialNumber='".$serialnumber."' 
AND d.keyParam='G002' AND r.EventKey = 'G002' 
ORDER BY h.timestamp DESC LIMIT 1"; 

Answer 3

变化

AND h.serialNumber=$serialnumber 

分成

AND h.serialNumber='$serialnumber' 

这将捕获任何空的$ serialnumber或带有字母的$ serialnumber。