按照前序非递归遍历二叉树，递归法将二叉树的左右子树互换-In accordance with the pre-order traversal non-recursive binary tree, binary tree recursive method will swap the left and right subtree
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001003s ]
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:0.068177s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.000972s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001114s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001093s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003105s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000816s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003840s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015943s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001547s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 269939 [ RunTime:0.015454s ]
