select * from content_task_file_1018_cn where locate('.png',screenshot) = 0 limit 10;
update content_task_file_1018_cn set screenshot=MD5(CONCAT(task_url,'境内')) where screenshot is null ;
update content_task_file_1018_cn set screenshot=MD5(CONCAT(task_url,'境内')) where is_open ='打开' ;
update content_task_file_1018_cn set screenshot=CONCAT(screenshot,'.png') where locate('.png',screenshot)=0 ;