输入集合个数及相应集合，指定子集和，然后回溯求解所有可能组合。-Enter the collection number and the corresponding collection and specify a subset, and then go back to solve all the possible combinations.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001367s ]
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:0.090026s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001222s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.002226s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001778s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003771s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001073s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003222s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014785s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001296s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 137526 [ RunTime:0.001473s ]
