一.问题描述

1.举个栗子

入参：userIdList=[75,76];id=null

    <select id="selectUserId" resultType="java.lang.Long">
        select
            user_id
        from
            user_student_info
        WHERE
            deleted = 0
            <if test="userIdList !=null and userIdList.size()>0">
              and user_id in
                <foreach collection="userIdList" item="id" open="(" separator="," close=")">
                    #{id}
                </foreach>
            </if>
        <if test="id!=null">
            and gradeId = #{id}
        </if>
    </select>

预期运行sql应该不会有and gradeId =

用mybatis sql log工具查看运行sql如下：【与预期不符合】

select user_student_info_id
 FROM user_student_info
 WHERE deleted = 0 and user_id in ( 75 , 76 ) and gradeId = 76;

将<foreach>中的item="id"改为item="item"就不会有and gradeId =

二.总结

在foreach标签item取名时避免和入参名一致，index的名字也是一样

原文地址：https://blog.csdn.net/queshuihaimian/article/details/98489239