google-bigquery - BigQuery：即使在应用别名后列名也不明确

Question

亲爱的 Stackoverflow 社区，

我正在尝试运行查询以使用别名在一个键上连接两个数据集，但验证器显示错误 Query error: Column name visit_id is ambiguous

SELECT visit_id as a
FROM `dashboards.test.visits` FULL JOIN `dashboards.test.tracks` on visit_id;

**Schema for `dashboards.test.visits`**

Field name  Type    Mode    
visit_time  TIMESTAMP   NULLABLE    
visit_id    INTEGER NULLABLE    
device_id   INTEGER NULLABLE    
traffic_source  STRING  NULLABLE    
pages_viewed    FLOAT   NULLABLE    

**Schema `dashboards.test.tracks`**

Field name  Type    Mode    
track_time  TIMESTAMP   NULLABLE    
track_id    FLOAT   NULLABLE    
visit_id    FLOAT   NULLABLE    

标签： google-bigquery

Answer 1

歧义在于该列的来源，因为它可以来自访问和跟踪。尝试以下操作：

SELECT a.visit_id
FROM `dashboards.test.visits` a
FULL JOIN `dashboards.test.tracks` b
on a.visit_id = b.visit_id;