MyBatis-Plus实现跨表查询并返回分页

@Getter
@Setter
@ToString
public class SupplierIdParam extends PageQueryParam {
    private Long tenantId;                        // 租户ID
    private Long supplierId;                      // 供应商ID
    private String materialCategoryExternalCode;  // 物料分类外部编码
    private String materialCategoryName;          // 物料分类名称
    private String materialName;                  // 物料名称
    private String materialExternalCode;          // 物料编码
    private String materialStatus;                // 物料状态
    private String pricingType;                   // 定价类型
    // ... 其他字段
}

@Getter
@Setter
@TableName(value = "t_supplier_material", autoResultMap = true)
public class SupplierMaterialDO implements BaseEntity {
    private Long id;
    private Long tenantId;
    private Long supplierDataId;
    private Long materialCategoryId;
    private String materialCategoryExternalCode;
    private String materialCategoryName;
    private Long materialId;
    private String externalCode;
    private String name;
    // ... 其他字段
}

@Repository
public class SupplierMaterialRepository extends HussarServiceImpl<SupplierMaterialMapper, SupplierMaterialDO> {
    @Resource
    private SupplierMaterialMapper supplierMaterialMapper;
    public Page<SupplierMaterialDO> queryMaterialsBySupplierId(SupplierIdParam param) {
        Long tenantId = param.getTenantId();
        // 第一步：查询总数
        Long total = supplierMaterialMapper.queryMaterialsBySupplierIdCount(param, tenantId);
        // 第二步：创建分页对象
        Page<SupplierMaterialDO> page = new Page<>(param.getCurrentPage(), param.getPageSize(), total);
        // 第三步：查询分页数据
        List<SupplierMaterialDO> supplierMaterialDOList = 
            supplierMaterialMapper.queryMaterialsBySupplierId(param, tenantId, page.offset(), page.getSize());
        // 第四步：设置结果集
        if (CollectionUtils.isNotEmpty(supplierMaterialDOList)) {
            page.setRecords(supplierMaterialDOList);
        }
        return page;
    }
}

@Mapper
public interface SupplierMaterialMapper extends BaseMapper<SupplierMaterialDO>, HussarMapper<SupplierMaterialDO> {
    
    /**
     * 查询总数
     */
    Long queryMaterialsBySupplierIdCount(@Param("param") SupplierIdParam param, 
                                         @Param("tenantId") Long tenantId);
    
    /**
     * 查询分页数据
     */
    List<SupplierMaterialDO> queryMaterialsBySupplierId(@Param("param") SupplierIdParam param, 
                                                        @Param("tenantId") Long tenantId, 
                                                        @Param("offset") Long offset, 
                                                        @Param("size") Long size);
}

<select id="queryMaterialsBySupplierIdCount" resultType="java.lang.Long">
    SELECT count(*) AS total
    FROM t_supplier_material tsm
    LEFT JOIN t_material tm ON tsm.material_id = tm.id
    WHERE tsm.delete_flag = '0'
    AND tsm.tenant_id = #{tenantId}
    <if test="param.supplierId != null and param.supplierId != ''">
        AND supplier_id = #{param.supplierId}
    </if>
    <if test="param.materialCategoryExternalCode != null and param.materialCategoryExternalCode != ''">
        AND tsm.material_category_external_code LIKE CONCAT('%', #{param.materialCategoryExternalCode}, '%')
    </if>
    <if test="param.materialCategoryName != null and param.materialCategoryName != ''">
        AND tsm.material_category_name LIKE CONCAT('%', #{param.materialCategoryName}, '%')
    </if>
    <if test="param.materialName != null and param.materialName != ''">
        AND tsm.name LIKE CONCAT('%', #{param.materialName}, '%')
    </if>
    <if test="param.materialExternalCode != null and param.materialExternalCode != ''">
        AND tsm.external_code LIKE CONCAT('%', #{param.materialExternalCode}, '%')
    </if>
    <if test="param.materialStatus != null and param.materialStatus != ''">
        AND tm.status = #{param.materialStatus}
    </if>
    <if test="param.pricingType != null and param.pricingType != ''">
        AND tm.pricing_type = #{param.pricingType}
    </if>
</select>

<select id="queryMaterialsBySupplierId"
        resultType="com.mdgyl.hussar.basic.supplier.masterdata.domain.SupplierMaterialDO">
    SELECT tsm.*
    FROM t_supplier_material tsm
    LEFT JOIN t_material tm ON tsm.material_id = tm.id
    WHERE tsm.delete_flag = '0'
    AND tsm.tenant_id = #{tenantId}
    <!-- 动态条件与COUNT查询保持一致 -->
    <if test="param.supplierId != null and param.supplierId != ''">
        AND supplier_id = #{param.supplierId}
    </if>
    <if test="param.materialCategoryExternalCode != null and param.materialCategoryExternalCode != ''">
        AND tsm.material_category_external_code LIKE CONCAT('%', #{param.materialCategoryExternalCode}, '%')
    </if>
    <!-- ... 其他动态条件 ... -->
    ORDER BY tsm.id DESC
    LIMIT #{offset}, #{size}
</select>