jeecgboot multi-table join query pagination

illustrate:

Jeecgboot uses mybatis plus, and uses the QueryWrapper object in the condition constructor to complete the query. The getCustomSqlSegment() method in this object is to obtain custom SQL: so, we use QueryWrapper to construct and obtain the custom SQL in the
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mapper Define SQL to be spliced after our join table query statement.

Mybatis plus document address: mybatis plus querywrapper

Code process:

My requirement: According to the openid query to the result data that has been done, the result data needs to be obtained by joint table query:
front end [small program]:

wx.request({
    
    
      url: getPayResultListByOpenId,
      data: {
    
    
        pageNo: this.data.page,
        pageSize: this.data.limit,
        openId: wx.getStorageSync('openid')
      },
      success: (res) => {
    
    
       },
      fail: (res) => {
    
    
        console.log(res);
      }
    })

controller:

 @RequestMapping(value = "getPayResultListByOpenId")
    @ResponseBody
    public Result<?> queryPageList(PayTestresult payTestresult,
                                   @RequestParam(name = "pageNo", defaultValue = "1") Integer pageNo,
                                   @RequestParam(name = "pageSize", defaultValue = "10") Integer pageSize,
                                   HttpServletRequest req) {
    
    
        QueryWrapper<PayTestresult> queryWrapper = QueryGenerator.initQueryWrapper(payTestresult, req.getParameterMap());
        Page<PayTestresult> page = new Page<PayTestresult>(pageNo, pageSize);
        IPage<PayTestresult> pageList = payTestresultService.pageList(page, queryWrapper);
        return Result.OK(pageList);
    }

service，serviceimpl：


IPage<PayTestresult> pageList(Page<PayTestresult> page, QueryWrapper<PayTestresult> queryWrapper);


@Overridepublic IPage<PayTestresult> pageList(Page<PayTestresult> page, QueryWrapper<PayTestresult> queryWrapper) {
    
    
        return testresultMapper.getPageList(page, queryWrapper);
}

mapper layer:

IPage<PayTestresult> getPageList(Page page, @Param(MybatisPlusConst.QUERYWRAPPER) Wrapper<PayTestresult> queryWrapper);

MybatisPlusConst is a custom constant class, and QUERYWRAPPER is a custom field

public class MybatisPlusConst {
    
    
    public static final String QUERYWRAPPER = "ew";
    public static final String SQL = "sql";
}

SQL statement in the mapper layer: use ${ew.customSqlSegment} to get the custom SQL statement, splicing

<select id="getPageList" resultType="org.jeecg.modules.paytest.entity.PayTestresult">
        SELECT b.descp, b.que_count, b.read_num, b.pic AS picPath, a.*
        FROM pay_testresult a
        LEFT JOIN pay_test b ON a.test_id = b.id
        ${ew.customSqlSegment}
    </select>

result:

The printed SQL statement is as follows:
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