遍历是二叉树各种操作的基础，显示，遍历过程中可以对各结点进行各种操作，又实现各种的目的。-traverse binary tree is the basis for various operations, that the process can traverse the nodes of various operations, Also achieve various objectives.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.005773s ]
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:0.089401s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.002322s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001918s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.002070s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003620s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.002060s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003407s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014866s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.002342s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 159299 [ RunTime:0.001228s ]
