"expression is neither present in the group by, nor is it an aggregate function"这里有什么问题？

Question

我正尝试在我的数据框上应用一个数据透视表，如下所示

val pivot_company_model_vals_df =  company_model_vals_df.groupBy("company_id","id","date")
                          .pivot("code")
                          .agg( when( col("data_item_value_numeric").isNotNull,  
      first("numeric")).otherwise(first("value")) )

错误

         org.apache.spark.sql.AnalysisException: expression '`data_item_value_numeric`' is neither present in the group by, nor is it an aggregate function. 

你能帮我看看我做错了什么吗？ 谢谢

Answer 1

修复了 first 如下移动 .agg( first(when 的问题：

val pivot_company_model_vals_df =  company_model_vals_df.groupBy("company_id","model_id","data_date")
                          .pivot("code")
                          .agg( first(when( col("data_item_value_numeric").isNotNull,  
      col("numeric")).otherwise(col("_string")) ) )