MyBatis 的动态 SQL 特性来实现有值字段才进行插入或更新

MyBatis 动态 SQL 解决方案

XML 复制代码

<!-- 动态INSERT语句 -->
<insert id="addDailyFreezeTer" parameterType="com.linyang.pecker.pojo.DailyFreezeTerminalBean">
    INSERT INTO dailyfreezeter_info
    <trim prefix="(" suffix=")" suffixOverrides=",">
        checkId, terminalId, pointId, meterNo, dataDate, saveDate, stepFlag,
        <if test="day_050601FF != null">day_050601FF,</if>
        <if test="day_050602FF != null">day_050602FF,</if>
        <if test="day_050603FF != null">day_050603FF,</if>
        <if test="day_050604FF != null">day_050604FF,</if>
        <if test="day_050605FF != null">day_050605FF,</if>
        <if test="day_050606FF != null">day_050606FF,</if>
        <if test="day_050607FF != null">day_050607FF,</if>
        <if test="day_050608FF != null">day_050608FF,</if>
        <if test="day_E1008060 != null">day_E1008060,</if>
        <if test="day_E1008061 != null">day_E1008061,</if>
        <if test="day_E1008062 != null">day_E1008062,</if>
        <if test="day_E1008063 != null">day_E1008063,</if>
        <if test="day_040005FF != null">day_040005FF,</if>
        <if test="day_E1008031 != null">day_E1008031,</if>
    </trim>
    VALUES
    <trim prefix="(" suffix=")" suffixOverrides=",">
        #{checkId}, #{terminalId}, #{pointId}, #{meterNo}, #{dataDate}, #{saveDate}, #{stepFlag},
        <if test="day_050601FF != null">#{day_050601FF},</if>
        <if test="day_050602FF != null">#{day_050602FF},</if>
        <if test="day_050603FF != null">#{day_050603FF},</if>
        <if test="day_050604FF != null">#{day_050604FF},</if>
        <if test="day_050605FF != null">#{day_050605FF},</if>
        <if test="day_050606FF != null">#{day_050606FF},</if>
        <if test="day_050607FF != null">#{day_050607FF},</if>
        <if test="day_050608FF != null">#{day_050608FF},</if>
        <if test="day_E1008060 != null">#{day_E1008060},</if>
        <if test="day_E1008061 != null">#{day_E1008061},</if>
        <if test="day_E1008062 != null">#{day_E1008062},</if>
        <if test="day_E1008063 != null">#{day_E1008063},</if>
        <if test="day_040005FF != null">#{day_040005FF},</if>
        <if test="day_E1008031 != null">#{day_E1008031},</if>
    </trim>
</insert>

实现说明

动态 INSERT 语句

使用<trim>标签处理括号和逗号
通过<if>判断字段是否为 null，只有非 null 字段才会加入 SQL
suffixOverrides=","自动处理多余的逗号

XML 复制代码

<!-- 动态UPDATE语句 -->
<update id="updateDailyFreezeTer" parameterType="com.linyang.pecker.pojo.DailyFreezeTerminalBean">
    UPDATE dailyfreezeter_info
    <set>
        <if test="day_050601FF != null">day_050601FF = #{day_050601FF},</if>
        <if test="day_050602FF != null">day_050602FF = #{day_050602FF},</if>
        <if test="day_050603FF != null">day_050603FF = #{day_050603FF},</if>
        <if test="day_050604FF != null">day_050604FF = #{day_050604FF},</if>
        <if test="day_050605FF != null">day_050605FF = #{day_050605FF},</if>
        <if test="day_050606FF != null">day_050606FF = #{day_050606FF},</if>
        <if test="day_050607FF != null">day_050607FF = #{day_050607FF},</if>
        <if test="day_050608FF != null">day_050608FF = #{day_050608FF},</if>
        <if test="day_E1008060 != null">day_E1008060 = #{day_E1008060},</if>
        <if test="day_E1008061 != null">day_E1008061 = #{day_E1008061},</if>
        <if test="day_E1008062 != null">day_E1008062 = #{day_E1008062},</if>
        <if test="day_E1008063 != null">day_E1008063 = #{day_E1008063},</if>
        <if test="day_040005FF != null">day_040005FF = #{day_040005FF},</if>
        <if test="day_E1008031 != null">day_E1008031 = #{day_E1008031},</if>
        <if test="dataDate != null">dataDate = #{dataDate},</if>
        <if test="saveDate != null">saveDate = #{saveDate},</if>
        <if test="stepFlag != null">stepFlag = #{stepFlag},</if>
    </set>
    WHERE checkId = #{checkId}  <!-- 根据实际主键调整 -->
</update>

动态 UPDATE 语句

使用<set>标签自动处理 SET 关键字和逗号
同样通过<if>判断字段是否为 null
需要确保 WHERE 子句使用正确的主键或唯一标识

注意事项

对于必须字段（如 checkId, terminalId 等），建议在 Java 代码中确保其非空
如果字段类型是基本数据类型（如 int, long），需要改用包装类（Integer, Long）才能判断 null
对于日期类型字段，可能需要额外处理空字符串或默认值的情况