一个简单的利用查表法的反正切和正、余弦函数，在处理速度不快的单片机编程中，这是一个使用的方法。-The use of a simple arctangent look-up table method and positive, cosine function, the processing speed of microcontroller programming unpleasant, this is a method used.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001291s ]
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:0.112214s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.019583s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.006720s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001232s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.005757s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001124s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.004324s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.018146s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001044s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 157872 [ RunTime:0.020914s ]
