Mybatis-xml映射文件与动态SQL

 xml映射文件

 动态SQL

<where>
            <if test="name!=null">
                name like concat('%',#{name},'%')
            </if>
            <if test="username!=null">
                and username=#{username}
            </if>
        </where>

<!--    collection：遍历的集合-->
<!--    item:遍历出来的元素-->
<!--    separator:分隔符-->
<!--    open：遍历开始的字符-->
<!--    close：遍历结束的字符-->
    <delete id="delectIds">
        delete from emp where id in
        <foreach collection="ids" item="id" separator="," open="(" close=")">
            #{id}
        </foreach>
    </delete>