词法扫描并生成中间表达式，理解中间代码，将非后缀式用来表示的算术表达式转换为用逆波兰式来表示的算术表达式
-Lexical scanning and generate intermediate expression, understanding of intermediate code will be used to indicate the non-suffix type is converted to the arithmetic expressions using reverse Polish expression to represent the arithmetic
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001134s ]
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:0.069025s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001361s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001311s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001051s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.005731s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.011725s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.008649s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.017332s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001617s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 180583 [ RunTime:0.023686s ]
