问题描述
所以我是一个新的DBT用户，非常棒，但是我遇到了union_relations宏的问题。我正在向该函数提供关系，但是编译/运行查询未从该关系中找到任何列。
这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，此后应该有关系中的列，但是由于某些原因，这些列没有被拉入。我想知道这是否是因为我想要的关系暂时退出，目前尚未实现，所以我想知道这是否引起了问题。这是编译后的sql，CTE返回数据，但是由于某种原因，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,identification_code as identification_code,null as school_year,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"
),performance_levels as performance_level,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
),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
);
任何想法都会非常感谢！
解决方法
union_relations宏依赖于知道存储在信息模式中的关系（表/视图）中的哪些列。由于此模型是临时模型，因此信息模式中没有任何记录，这就是为什么这样的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dbt-utils的较早版本-尽管我们尚未解决此问题，但我们拥有improved the way this issue is handled（在v0.5.0中发布）。
较新版本的dbt-utils可以帮助您了解以下信息：
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，如（新）错误消息所暗示的那样，解决此问题的唯一方法是使上游模型成为视图或表。