实例：MyBatis-Plus自定义联表分页查询-动态sql实现

系列文章目录

第一篇：实例：MyBatis-Plus自定义分页查询
第二篇：实例：MyBatis-Plus自定义联表分页查询
第三篇：实例：MyBatis-Plus自定义联表分页查询-动态sql实现

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一、简介

高级检索所检索的项中，往往会存在对关联项的检索。
比如说，派车单高级检索，名称、派车日期等检索项在派车表内，但以所配送的具体产品编号作为检索项时，就必须做相应联表查询。

数据库模型如下：
派车单关联若干发货单，关联车辆(vehicle_id)，发货单关联若干发货单明细

二、关键代码

• WorksheetServiceImpl.java:

    /**
     * 派车单高级检索
     * @param param 检索项
     * @return
     */
    public IPage<WorksheetDetailsBean> queryWorksheet(SlWorksheetQueryExeParam param) throws Exception {
        Page<Worksheet> page1 = new Page<>(param.getPage(), param.getPagesize());
        return worksheetMapper.selectPageCusNew(page1, param);
    }

• WorksheetMapper.java:

    /**
     * 派车单高级检索
     * @param page1 分页对象
     * @param param 检索项
     * @return
     */
    IPage<WorksheetDetailsBean> selectPageCusNew(
            Page<Worksheet> page1,
            @Param("qryPm") SlWorksheetQueryExeParam param
    );

• WorksheetMapper.xml:

出于需求，此sql查询结果映射到了另一个类。
否则，用 resultType="com.xxxxx.api.model.WorksheetDetailsBean" 代替 resultMap="worksheetWithStoreAndSkuNum"

    <select id="selectPageCusNew" resultMap="worksheetWithStoreAndSkuNum">
        SELECT DISTINCT w.* FROM sl.sl_worksheet w
        <if test="qryPm.vehicleNo != null and qryPm.vehicleNo != ''">
            INNER JOIN sl.sl_vehicle v
                ON v.delete_time IS NULL AND w.vehicle_id = v.id AND v.license LIKE '%${qryPm.vehicleNo}%'
        </if>
        <if test="qryPm.productCode != null and qryPm.productCode != ''
        or qryPm.productName != null and qryPm.productName != ''">
            INNER JOIN sl.sl_delivery dly
                ON dly.delete_time IS NULL AND w.name = dly.worksheet_no
            INNER JOIN sl.sl_delivery_to_line d2l
                ON d2l.delete_time IS NULL AND dly.id = d2l.delivery_id
            INNER JOIN sl.sl_delivery_line dl
                ON dl.delete_time IS NULL AND d2l.line_id = dl.id
                <if test="qryPm.productCode != null and qryPm.productCode != ''">
                    AND dl.code LIKE '%${qryPm.productCode}%'
                </if>
                <if test="qryPm.productName != null and qryPm.productName != ''">
                    AND dl.name LIKE '%${qryPm.productName}%'
                </if>
        </if>
        WHERE w.delete_time IS NULL AND w.oid = #{qryPm.oid}
        <if test="qryPm.rosteringId != null"> AND w.rostering_id = #{qryPm.rosteringId}</if>
        <if test="qryPm.state != null and qryPm.state != ''"> AND w.status = #{qryPm.state}</if>
        <if test="qryPm.handlerPartnerIdList != null"> AND w.handler_partner_id IN
            <foreach collection="qryPm.handlerPartnerIdList" item="handlerPid" open="(" close=")" separator=",">
                #{handlerPid}
            </foreach>
        </if>
        <if test="qryPm.startCreateTime != null and qryPm.endCreateTime != null">
            AND w.create_time BETWEEN #{qryPm.startCreateTime} AND #{qryPm.endCreateTime}
        </if>
        <if test="qryPm.worksheetName != null and qryPm.worksheetName != ''">
            AND w.name LIKE '%${qryPm.worksheetName}%'
        </if>
        ORDER BY w.create_time DESC, w.id DESC
    </select>

三、总结

• xml自定义sql中，通过mybatis的动态sql（标签）判断是否需要联表查询。有两处联表查询，分别检索派车单关联的车辆及配送产品。

• 上述实例联表查询的结果会产生重复问题，需使用 DISTINCT w.* 去重。
  当然，如非此例的针对派车单的查询，无需去重。

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MyBatis相关教程：
MyBatis教程
MyBatis-Plus官方文档

本文地址：https://blog.csdn.net/ymzhaobth/article/details/112568161