Mybatisplus 自定义sql 使用条件构造器 多表查询分页

代码示例：

    Page<Handling> finPage(@Param("page") Page<Handling> page,@Param(Constants.WRAPPER) QueryWrapper<Handling> qw);

　　

<select id="finPage" resultType="com.zw.zwzc.module.business.entity.Handling">
        select *
        from (
                 SELECT a.*,
                        b.user_name,
                        c.area_code,
                        c.dept_name,
                        d.implement_name,
                        d.event_type,
                        ap.applicant_name,
                        ha.handler_name,
                        if(a.applicant_id is null, "N", "Y") is_to_do
                 FROM handling a
                          LEFT JOIN sys_user b ON b.user_id = a.user_id
                          LEFT JOIN sys_dept c ON c.dept_id = b.dept_id
                          left join event_implementation d on d.event_id = a.event_id
                          left join applicant ap on ap.applicant_id = a.applicant_id
                          left join handler ha on ha.handler_id = a.handler_id
             ) tab
            ${ew.customSqlSegment}
    </select>

条件设置：

@Override
    public Page<Handling> findPage(Page<Handling> page, Handling en) throws Exception {
        QueryWrapper<Handling> qw = new QueryWrapper<>();

        //区分代办查询和已办查询（如果不传状态 默认查询代办[去除办理成功数据]）
        if (StrUtil.isNotEmpty(en.getState())) {
            qw.eq("tab.state", en.getAreaCode());
        }else {
            qw.ne("tab.state", CommonConstant.SUCCESS);
        }

        // 办件查询添加环节筛选需求
        if (StrUtil.isNotEmpty(en.getBusinessTacheId())) {
            qw.eq("tab.business_tache_id", en.getBusinessTacheId());
        }

        if (StrUtil.isNotEmpty(en.getAreaCode())) {
            qw.eq("tab.area_code", en.getAreaCode());
        }

        if (StrUtil.isNotEmpty(en.getUserName())) {
            qw.eq("tab.user_name", en.getUserName());
        }

        if (StrUtil.isNotEmpty(en.getDeptName())) {
            qw.eq("tab.dept_name", en.getDeptName());
        }
        if (StrUtil.isNotEmpty(en.getEventType())) {
            qw.eq("tab.event_type", en.getEventType());
        }

        if (StrUtil.isNotEmpty(en.getSearch())) {
            qw.like("tab.applicant_name", en.getSearch()).or().like("tab.implement_name", en.getSearch());
        }
        if (en.getStartDate() != null && !en.getStartDate().equals("")) {
            qw.ge("tab.start_date", en.getStartDate());
        }
        if (en.getEndDate() != null && !en.getEndDate().equals("")) {
            qw.le("tab.start_date", en.getEndDate());
        }
        if (StringUtils.isNotBlank(en.getIsOneThing())) {
            qw.eq("tab.is_one_thing", en.getIsOneThing());
        }
        if (StringUtils.isNotBlank(en.getIsTongBan())) {
            qw.eq("tab.is_tong_ban", en.getIsTongBan());
        }

        Page<Handling> handlingPage = baseMapper.finPage(page, qw);
        //翻译state字段
        dictItemService.setDescByValue(handlingPage.getRecords(),"state","stateName","handling_state");
        //添加时限信息
        addTimeLimitDesc(handlingPage);

        return handlingPage;
    }

可以少在XML里面写条件了