链接mysql 504_phpMyAdmin错误代码：504 MySQL查询
我对SQL一般还是比较新的 . 我在phpMyAdmin中尝试以下查询 .
SELECT i.`ITEM_NO` as SKU,
i.`DESCR` as Description,
(SELECT SUM(`QTY_SOLD`)
FROM `ps_tkt_hist_lin`
WHERE `ITEM_NO` = i.`ITEM_NO`
AND `BUS_DAT` >= MAKEDATE(YEAR(CURDATE()),1)
) as 'QTY Sold YTD',
(SELECT SUM(`QTY_SOLD`)
FROM `ps_tkt_hist_lin`
WHERE `ITEM_NO` = i.`ITEM_NO`
AND `BUS_DAT` >= DATE_SUB(DATE_SUB(CURDATE(),INTERVAL (DAY(CURDATE())-1) DAY), INTERVAL 1 MONTH)
) as 'QTY Sold Last Month',
(SELECT SUM(`QTY_ON_HND`)
FROM `IM_INV`
WHERE `ITEM_NO` = i.`ITEM_NO`
AND `LOC_ID` IN ('SL','S','LO','AF')
) as 'QTY on Hand'
FROM `ps_tkt_hist_lin` as i
WHERE i.`ITEM_VEND_NO` = 'MD'
GROUP BY i.`ITEM_NO`, i.`DESCR`
ORDER BY i.`ITEM_NO`
运行时出现以下错误 .
Error in processing request
Error code: 504
Error text: Gateway Time-out (rejected)
It seems that the connection to server has been lost. Please check your network connectivity and server status.
如果有帮助，这是服务器信息：
服务器：通过UNIX套接字的Localhost服务器类型：MariaDB服务器版本：10.1.31-MariaDB - MariaDB服务器cpsrvd 11.68.0.29数据库客户端版本：libmysql - 5.1.73 PHP版本：5.6.30
Thanks in advance for patiently helping a dude just getting started with SQL and MySQL.