该文件是关于状态反馈和观测器的习题，里面的习题均有完整的解答，对学习的朋友很有帮助。欢迎下载！-the document on state feedback and observation of exercises, which are the integrity of the questions to answer, learning helpful friends. Welcome to download!
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.000960s ]
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:0.064467s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001006s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001166s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001041s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003013s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000875s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003611s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014255s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001096s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 131149 [ RunTime:0.019461s ]
