30. Spark SQL case when用法：

30.

Spark SQL case when用法：

https://sparkbyexamples.com/spark-case-when-otherwise-example/

how to write case with when condition in spark sql using scala - Stack Overflow

scala - SPARK SQL: Implement AND condition inside a CASE statement - Stack Overflow

上述几个帖子已经写得很详细了，我就不再赘述，只放出链接。

Spark Sql 使用Case when，存在多个when条件的代码示例：

SPARK SQL - case when then - Stack Overflow

伪代码：

select
                             CASE WHEN company_base = 'ah' THEN '安徽' 
                                   ELSE
                                       CASE WHEN company_base = 'bj' THEN '北京'
                                   ELSE    
                                       CASE WHEN company_base = 'cq' THEN '重庆'
                                   ELSE    
                                       CASE WHEN company_base = 'fj' THEN '福建'
                                   ELSE    
                                       CASE WHEN company_base = 'gd' THEN '广东'
                                   ELSE    
                                       CASE WHEN company_base = 'gx' THEN '广西'
                                   ELSE    
                                       CASE WHEN company_base = 'gs' THEN '甘肃'                                       
                                   ELSE    
                                       CASE WHEN company_base = 'gz' THEN '贵州'
                                   ELSE    
                                       CASE WHEN company_base = 'han' THEN '海南'
                                   ELSE    
                                       CASE WHEN company_base = 'heb' THEN '河北'
                                   ELSE    
                                       CASE WHEN company_base = 'hen' THEN '河南'
                                   ELSE    
                                       CASE WHEN company_base = 'hlj' THEN '黑龙江'
                                   ELSE    
                                       CASE WHEN company_base = 'hub' THEN '湖北'
                                   ELSE    
                                       CASE WHEN company_base = 'hun' THEN '湖南'
                                   ELSE    
                                       CASE WHEN company_base = 'jl' THEN '吉林'
                                   ELSE    
                                       CASE WHEN company_base = 'js' THEN '江苏'
                                   ELSE    
                                       CASE WHEN company_base = 'jx' THEN '江西'
                                   ELSE    
                                       CASE WHEN company_base = 'ln' THEN '辽宁'
                                   ELSE    
                                       CASE WHEN company_base = 'nmg' THEN '内蒙古'
                                   ELSE    
                                       CASE WHEN company_base = 'nx' THEN '宁夏'                                                                                
                                   ELSE    
                                       CASE WHEN company_base = 'sc' THEN '四川'
                                   ELSE
                                       CASE WHEN company_base = 'sd' THEN '山东'
                                   ELSE    
                                       CASE WHEN company_base = 'sh' THEN '上海'
                                   ELSE    
                                       CASE WHEN company_base = 'snx' THEN '陕西'
                                   ELSE
                                       CASE WHEN company_base = 'sx' THEN '山西'
                                   ELSE
                                       CASE WHEN company_base = 'tj' THEN '天津'
                                   ELSE
                                       CASE WHEN company_base = 'xj' THEN '新疆'
                                   ELSE
                                       CASE WHEN company_base = 'xz' THEN '西藏'
                                   ELSE
                                       CASE WHEN company_base = 'yn' THEN '云南'
                                   ELSE
                                       CASE WHEN company_base = 'zj' THEN '浙江'
                                   ELSE
                                       CASE WHEN company_base = 'qh' THEN '青海'   
                                   ELSE
                                       CASE WHEN company_base = 'tw' THEN '台湾'
                                   ELSE '未知' 
                                   END END END END END END END END END END END END END 
                                   END END END END END END END END END END END END END
                                   END END END END END END
     AS  company_base
from company
group by company_name 

此贴来自汇总贴的子问题，只是为了方便查询。

总贴请看置顶帖：

pyspark及Spark报错问题汇总及某些函数用法。

pyspark及Spark报错问题汇总及某些函数用法。_元元的李树的博客-CSDN博客