xib连线问题 Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key backButton.' 跳转问题,直接present到另一个ViewController上Warning: Attempt to present on who
不同于oracle和sqlserver,mysql并不支持在更新某个表的数据时又查询了它,而查询的数据又做了更新的条件,因此我们需要使用如下的语句绕过: UPDATE teaching_department SET code_year = 2017, notice_code = (SELECT a.code + 1 FROM (SELECT MAX(notice_code) code FROM teaching_department WHERE department_id = 6284 and