php - 这个 MySQL 查询语法有什么问题？

Question

$db = mysql_select_db("remote"); 

if(!$db) {
    die("Unable to select database");
} 

$query = "SET @cumulative_sum := 0; 
          SELECT timestamp, 
                 @cumulative_sum := @cumulative_sum + value AS cumulative_sum 
          FROM remote.historical 
          WHERE timestamp>= CURDATE()"; 

$result = mysql_query($qry);

当我在 HeidiSQL 中使用此查询时，它输出正常...当天运行累积，但是当我将此代码复制到 php 文件中时，网络浏览器输出:

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 'SELECT timestamp, @cumulative_sum := @cumulative_sum + value AS cumulative_sum F' at line 1

这段代码有什么问题？

Answer 1

您可以选择在子查询中声明变量，而不是执行两条语句，例如。

SELECT  timestamp, 
        @cumulative_sum := @cumulative_sum + value AS cumulative_sum 
FROM    remote.historical, (SELECT @cumulative_sum := 0) b
WHERE timestamp>= CURDATE()