传输距离：lora城镇可达2-5 Km ， 郊区可达15 Km 。工作频率：ISM 频段 包括433。标准：IEEE 802.15.4g。调制方式：基于扩频技术，线性调制扩频（CSS）的一个变种，具有前向纠错（FEC）能力，semtech公司私有专利技术。容量：一个LoRa网关可以连接上千上万个LoRa节点
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001637s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.087562s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001052s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001187s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000957s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003083s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000788s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003917s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014949s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001262s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 279705 [ RunTime:0.011152s ]
