MybatisPlus自定义SQL如何支持多表分页查询

MybatisPlus自定义SQL如何支持多表分页查询

前言

在本文，详细写一下使用mapper.xml实现mybatisplus多条件分页查询的写法。

---

一、介绍

其实还是比较简单的，直接看下面的需求：

数据库图和多条件查询页面的图如上所示。

二、QueryVo

首先根据要查询的条件，定义相应的QueryVo类。

package com.jztai.cellpathology.pojo;

import lombok.Data;

import java.util.Date;

@Data
public class SampleQueryVo {
    private String sampleNum;
    private String patientName;
    private Integer patientAge;
    private Integer sampleType;
    private Integer reportType;
    private Date sampleStartSendDate;
    private Date sampleEndSendDate;
    private Date sampleStartDate;
    private Date sampleEndDate;
    private Integer sampleStatus;
    private Integer instiutionId;
    private Integer doctorId; // 送检医生编号
}

二、Controller层

@GetMapping("samples/page/{page}/size/{size}")
    @ApiOperation("分页查询所有的接口")
    public Page<SamplePageVo> list(SampleQueryVo sampleQueryVo, String name, @PathVariable("page") Integer pagenum, @PathVariable("size") Integer size) {
        Page<SamplePageVo> userPage = sampleService.listSamplePage(sampleQueryVo, pagenum, size);
        return userPage;
    }

三、Service层

public interface SampleService extends IService<TbSample> {

    Page<SamplePageVo> listSamplePage(SampleQueryVo queryVo,Integer page,Integer size);
}

下面是实现

@Service
public class SampleServiceImpl extends ServiceImpl<TbSampleMapper, TbSample> implements SampleService {

    @Override
    public Page<SamplePageVo> listSamplePage(SampleQueryVo queryVo, Integer page, Integer size) {
        // 构造分页参数
        Page<SamplePageVo> pages = new Page<SamplePageVo>(page, size);
        // 在这里封装where条件
        QueryWrapper<SamplePageVo> queryWrapper = new QueryWrapper<SamplePageVo>();
        // baseMapper就是指代的TbSampleMapper类。
        return this.baseMapper.selectSamplePageVoPage(pages, queryWrapper);
    }
}

四、Mapper层

4.1 Mapper类

public interface TbSampleMapper extends BaseMapper<TbSample> {
	
	// 直接按照这个格式写
	// 加上Page page即可实现分页， @Param("ew")指定在封装Sql的时候的参数名
    Page<SamplePageVo> selectSamplePageVoPage(Page<SamplePageVo> page, @Param("ew") Wrapper<SamplePageVo> queryWrapper);

}

4.2 多表查询的sql

这里特别注意的是，我在查主表的时候，字段不改名，在查询子表的时候字段名改成 Javabean的属性名.字段名 ，mybatisplus会自动将字段封装到指定的bean里面，也可能是mybatis都这样处理的，我记得之前在新冠报告项目里面mybatis好像没有给封装，需要自己写ResultMap建立映射的。

SELECT  sample_id,creater.user_id as 'creater.user_id',creater.user_name  AS 'creater.user_name',updater.user_id AS 'updater.user_id',updater.user_name AS 'updater.user_name',patient.patient_id AS 'patient.patient_id',patient.patient_name AS 'patient.patient_name',institution.instiution_id AS 'institution.instiution_id',institution.institution_name AS 'institution.institution_name',department.instiution_id AS 'department.instiution_id',department.institution_name AS 'department.institution_name',doctor.user_id AS 'doctor.user_id',doctor.user_name AS 'doctor.user_name',sample.update_time AS 'sample.update_time',telephone,samplestatus.dict_id AS 'samplestatus.dict_id',samplestatus.dict_value AS 'samplestatus.dict_value',sampletype.dict_id AS 'sampletype.dict_id',sampletype.dict_value AS 'sampletype.dict_value',reporttype.dict_id AS 'reporttype.dict_id',reporttype.dict_value AS 'reporttype.dict_value',sample_date,sample_send_date,sample.remark,diagnosticiandoc.user_id,diagnosticiandoc.user_name
FROM tb_sample AS sample 
LEFT JOIN tb_user AS creater ON sample.creater_id = creater.user_id
LEFT JOIN tb_user AS updater ON sample.updater_id = updater.user_id
LEFT JOIN tb_user AS doctor ON sample.updater_id = doctor.user_id
LEFT JOIN tb_patient AS patient ON patient.patient_uuid = sample.patient_uuid
LEFT JOIN tb_institution AS institution ON institution.instiution_id = sample.instiution_id
LEFT JOIN tb_institution AS department ON department.instiution_id = sample.department_id
LEFT JOIN tb_dictionary AS sampletype ON sample.sample_type = sampletype.dict_id
LEFT JOIN tb_dictionary AS reporttype ON sample.report_type = reporttype.dict_id
LEFT JOIN tb_dictionary AS samplestatus ON sample.sample_status = samplestatus.dict_id
LEFT JOIN tb_user AS diagnosticiandoc ON sample.diagnostician = diagnosticiandoc.user_id
LEFT JOIN tb_user AS reviewer ON sample.review_doctor = reviewer.user_id

where
// 后面跟查询条件，此处省略。

4.3 Mapper.xml

<sql id="Base_Column_List_With_ALL_MESSAGE">
        sample_id
        ,creater.user_id as 'creater.user_id',
        creater.user_name  AS 'creater.user_name',
        updater.user_id AS 'updater.user_id',
        updater.user_name AS 'updater.user_name',
        patient.patient_id AS 'patient.patient_id',
        patient.patient_name AS 'patient.patient_name',
        institution.instiution_id AS 'institution.instiution_id',
        institution.institution_name AS 'institution.institution_name',
        department.instiution_id AS 'department.instiution_id',
        department.institution_name AS 'department.institution_name',
        doctor.user_id AS 'doctor.user_id',
        doctor.user_name AS 'doctor.user_name',
        sample.update_time AS 'sample.update_time',
        telephone,samplestatus.dict_id AS 'samplestatus.dict_id',
        samplestatus.dict_value AS 'samplestatus.dict_value',
        sampletype.dict_id AS 'sampletype.dict_id',
        sampletype.dict_value AS 'sampletype.dict_value',
        reporttype.dict_id AS 'reporttype.dict_id',
        reporttype.dict_value AS 'reporttype.dict_value',
        sample_date,sample_send_date,sample.remark,
        diagnosticiandoc.user_id,diagnosticiandoc.user_name
sql>

 <resultMap id="BaseResultMap"
               type="com.jztai.cellpathology.pojo.SamplePageVo">
        <id column="sample_id" property="sampleId" jdbcType="INTEGER"/>
        <result column="sample_date" property="sampleDate"
                jdbcType="DATETIMEOFFSET"/>
        <result column="sample_send_date" property="sampleSendDate"
                jdbcType="DATETIMEOFFSET"/>
        <result column="sample.remark" property="remark"
                jdbcType="VARCHAR"/>
resultMap>

 <select id="selectSamplePageVoPage"
            parameterType="com.jztai.cellpathology.pojo.SampleQueryVo"
            resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List_With_ALL_MESSAGE"/>
        FROM tb_sample AS sample
        LEFT JOIN tb_user AS creater ON sample.creater_id = creater.user_id
        LEFT JOIN tb_user AS updater ON sample.updater_id = updater.user_id
        LEFT JOIN tb_user AS doctor ON sample.updater_id = doctor.user_id
        LEFT JOIN tb_patient AS patient ON patient.patient_uuid = sample.patient_uuid
        LEFT JOIN tb_institution AS institution ON institution.instiution_id = sample.instiution_id
        LEFT JOIN tb_institution AS department ON department.instiution_id = sample.department_id
        LEFT JOIN tb_dictionary AS sampletype ON sample.sample_type = sampletype.dict_id
        LEFT JOIN tb_dictionary AS reporttype ON sample.report_type = reporttype.dict_id
        LEFT JOIN tb_dictionary AS samplestatus ON sample.sample_status = samplestatus.dict_id
        LEFT JOIN tb_user AS diagnosticiandoc ON sample.diagnostician = diagnosticiandoc.user_id
        LEFT JOIN tb_user AS reviewer ON sample.review_doctor = reviewer.user_id

		
        <if test="ew.emptyOfWhere == false">
            ${ew.customSqlSegment}
        if>
    select>