DELETE FROM t_questions WHERE Id in ( SELECT Id FROM ( SELECT Id FROM `t_questions` WHERE (Name,QuestionTypeId) ) AND Id NOT in (SELECT Id FROM `t_questions` WHERE Intention IS NOT NULL) ) as a )
MySql增加字段.删除字段.修改字段名称.修改字段类型 1.增加一个字段 alter table user add COLUMN new1 VARCHAR(20) DEFAULT NULL; //增加一个字段,默认为空 alter table user add COLUMN new2 VARCHAR(20) NOT NULL; //增加一个字段,默认不能为空 2.删除一个字段 alter table user DROP COLUMN new2; //删除一个字段 3.修改一个字段