【关联查询引用的数据混乱 _spring _mybatis 】

关联查询引用的数据混乱

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spring mybatis

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源码

  <!-- 根据分页数据start 和size查询数据 -->
    <select id="findByPage" parameterType="Map" resultType="Student">
        select * FROM students
        <if test="start!=null and size!=null">
            limit #{start},#{size}
        </if>
    </select>

    <!-- 查询用户记录总数 -->
    <select id="selectCount" resultType="int">
        select count(*) FROM `students`
    </select>

    <select id="findById" parameterType="long" resultType="Student">
        SELECT * FROM students WHERE id = #{id}
    </select>

    <select id="findByName" parameterType="java.lang.String" resultType="Student">
        SELECT * FROM students WHERE name LIKE '%${value}%'
    </select>

    <select id="findByNum" parameterType="java.lang.String" resultType="Student">
        SELECT * FROM students WHERE num = #{num}
    </select>

    <insert id="insertStudent" parameterType="Student">
        INSERT INTO students(name,qq,type,admission_time,school,num,daily,declaration,elder,knew_from,create_at) VALUE
        (#{name},#{qq},#{type},#{admissionTime},#{school},#{num},#{daily},#{declaration},#{elder},#{knewFrom},#{createAt})
        <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Long">
            select last_insert_id()
        </selectKey>
    </insert>

    <delete id="deleteStudent" parameterType="java.lang.Long">
        DELETE FROM students WHERE id = #{id}
    </delete>

    <update id="updateStudent" parameterType="Student">
        UPDATE students

        <set><!--set标签会去除只有最后一个条件的,-->
            <if test="updateAt!=null and updateAt!=''">
                update_at=#{updateAt},
                <if test="name!= null and name!=''">name = #{name},</if>
                <if test="QQ!= null and QQ!=''">QQ = #{QQ},</if>
                <if test="type!= null and type!=''">type = #{type},</if>
                <if test="admissionTime!= null and admissionTime!=''">admission_time = #{admissionTime},</if>
                <if test="school!= null and school!=''">school = #{school},</if>
                <if test="num!= null and num!=''">num = #{num},</if>
                <if test="daily!= null and daily!=''">daily = #{daily},</if>
                <if test="declaration!= null and declaration!=''">declaration = #{declaration},</if>
                <if test="elder!= null and elder!=''">elder = #{elder},</if>
                <if test="knewFrom!= null and knewFrom!=''">knew_from = #{knewFrom},</if>
            </if>
        </set>

        <where><!--where标签会去除第一个条件的and和or-->
            <if test="id!=null">AND id=#{id}</if>
        </where>
    </update>

</mapper>

编辑于2025-04-20

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[北京|结业弟子]JAVA-郭超
0

这种情况经常是查询返回的主键名字是相同的，从而导致返回结果出错。两张表的数据库字段相同，是难以避免的，需要结合使用 SQL语句别名和resultMap一起使用即可解决。

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编辑于2018-07-30

去第页