一、mapper.xml 头部文件: 二、查询 1.简单查询 SELECT * FROM BLOG state = #{state} title LIKE CONCAT ('%', #{title}, '%') 2.含 in 关键字的查询 SELECT * FROM BLOG id in #{id} 三、新增 1.单次 insert into news_comment newsid, author, #{newsid}, #{autho