使用DBT_utils.Union_Relationship是错误的，但不知道如何/为什么？ [英] Using dbt_utils.union_relations wrong but don't know how/why?

问题描述

我是一个新的DBT用户，非常酷，但我遇到了Union_Relationship宏的问题。我将关系提供给此函数，但编译/运行查询没有从关系中找到任何列。

以下是我正在运行的代码：

{{dbt_utils.union_relations(relations=[ref('transform_hist_ca_map_stu_obj_assessment'), ref('transform_hist_sc_map_stu_obj_assessment')])}}


)
select *
from conformed_obj_assessment
where student_assessment_identifier is not null
and assessment_identifier is not null
and identification_code is not null
and student_unique_id is not null
and performance_level is not null

这是我收到的错误： syntax error at or near "from" LINE 1706: from __dbt__CTE__transform_hist_ca_map_stu_obj_a... ^ compiled SQL at target/run/rally_dw/conformed/conformed_student_objective_assessment.sql

基本上，第一列是DBT生成的列，之后应该有来自关系的列，但出于某种原因，这些列没有被拉入。我想知道这是不是因为我想要摆脱的关系目前是短暂的，所以没有实现，所以我想知道这是否造成了问题。以下是编译后的SQL，CTE返回数据，但由于某种原因，它没有被拉到最后一个CTE中。

  create  table "dashboarding"."dev_em_conformed"."conformed_student_objective_assessment__dbt_tmp"
  as (
    
with  __dbt__CTE__historical_ca_map_stu_obj_assessment as (

with hist_ca_map_stu_obj_assess as (
    select * from "dashboarding"."raw_ea"."historical_ca_map_student_obj_assessment"
),
cleaned as (
    select distinct
        source_org,
        assessment_id as assessment_identifier,
        student_assessment_identifier,
        student_unique_id,
        performance_levels  as performance_level,
        scale_score as score,
        assessment_id,
        to_date(test_date, 'YYYY-MM-DD') as test_date,
        identification_code,
        null as parent_objective_assessment_name
    from hist_ca_map_stu_obj_assess
)
select * from cleaned
),  __dbt__CTE__transform_hist_ca_map_stu_obj_assessment as (

with hist_ca_stu_obj_assess as (
    select * from __dbt__CTE__historical_ca_map_stu_obj_assessment
),
final as(
select
    null as source_org,
    student_assessment_identifier,
    assessment_id as assessment_identifier,
    identification_code as identification_code,
    null as school_year,
    student_unique_id,
    null as student_grade_level,
    null as assessment_grade_level,
    NULL as administration_date,
    null as administration_end_date,
    null as objective_assessment_name,
    score,
    performance_level,
    parent_objective_assessment_name,
    null as parent_objective_assessment_id
from hist_ca_stu_obj_assess

)
select * from final
), __dbt__CTE__historical_sc_map_stu_obj_assessment as (

with hist_sc_map_soa as (
    select * from "dashboarding"."raw_ea"."historical_sc_map_student_obj_assessment"
),
cleaned as (
    select distinct
        source_org,
        assessment_id as assessment_identifier,
        student_assessment_identifier,
        student_unique_id,
        performance_levels as performance_level,
        scale_score as score,
        assessment_id,
        to_date(test_date, 'YYYY-MM-DD') as test_date,
        identification_code,
        null as parent_objective_assessment_name
    from hist_sc_map_soa
)
select * from cleaned
),  __dbt__CTE__transform_hist_sc_map_stu_obj_assessment as (

with hist_sc_stu_obj_assess as (
    select * from __dbt__CTE__historical_sc_map_stu_obj_assessment
),
final as(
select
    null as source_org,
    student_assessment_identifier,
    assessment_id as assessment_identifier,
    identification_code as identification_code,
    null as school_year,
    student_unique_id,
    null as student_grade_level,
    null as assessment_grade_level,
    NULL as administration_date,
    null as administration_end_date,
    null as objective_assessment_name,
    score,
    performance_level,
    parent_objective_assessment_name,
    null as parent_objective_assessment_id
from hist_sc_stu_obj_assess

)
select * from final
),  conformed_obj_assessment as(



        (
            select

                cast('__dbt__CTE__transform_hist_ca_map_stu_obj_assessment' as 
    varchar
) as _dbt_source_relation,
                ---NO MORE COLUMNS???

            from __dbt__CTE__transform_hist_ca_map_stu_obj_assessment
        )

        union all
        

        (
            select

                cast('__dbt__CTE__transform_hist_sc_map_stu_obj_assessment' as 
    varchar
) as _dbt_source_relation,
                 ---NO MORE COLUMNS??

            from __dbt__CTE__transform_hist_sc_map_stu_obj_assessment
        )

        


)
select *
from conformed_obj_assessment
where student_assessment_identifier is not null
and assessment_identifier is not null
and identification_code is not null
and student_unique_id is not null
and performance_level is not null

  );

如果您有任何想法，我们将不胜感激！

推荐答案

union_relations宏依赖于知道存储在信息架构中的关系(表/视图)中的哪些列。因为这个模型是短暂的，所以信息模式中没有任何记录，这就是为什么会有这样的SQL：

select

cast('__dbt__CTE__transform_hist_ca_map_stu_obj_assessment' as 
    varchar
) as _dbt_source_relation,

from __dbt__CTE__transform_hist_ca_map_stu_obj_assessment

我注意到您使用的是稍微旧一点的DBT-Utils版本-虽然我们尚未修复此问题，但我们已经improved the way this issue is handled(在v0.5.0中发布)。

较新版本的DBT-Utils将告诉您一些有用的信息：

Compilation Error in model test_ephemeral (models/test_ephemeral.sql)

  The `union_relations` macro cannot be used with ephemeral models, as it relies on the information schema.

  `__dbt__CTE__my_ephemeral` is an ephemeral model. Consider making is a view or table instead.` is an ephemeral model. Consider making is a view or table instead.

因此，正如(新的)错误消息所示-解决此问题的唯一方法是使您的上游模型成为视图或表。

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