MySQL查詢在命令行中運行良好，但在運行時出現錯誤php

Question

我的查詢在我的Linux服務器命令行上運行時運行正常，但當我嘗試通過php執行時，它會引發php錯誤。

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; 

它給我這個錯誤：

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

有誰知道什麼是錯？

Answer 1

我的猜測：$serialnumber是空的，你的查詢是：

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

更新查詢如下，它會更加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

變化

AND h.serialNumber=$serialnumber 

分成

AND h.serialNumber='$serialnumber' 

這將捕獲任何空的$ serialnumber或帶有字母的$ serialnumber。