Question

在Hive中具有具有以下结构的表：

 col1 col2 col3 col4 col5 col6
 -----------------------------
 AA   NM   ER   NER  NER  NER
 AA   NM   NER  ERR  NER  NER
 AA   NM   NER  NER  TER  NER
 AA   NM   NER  NER  NER  ERY

编写查询以从表中获取记录：

Select distinct(col1),col2, array(concat(
CASE WHEN col3=='ER'  THEN 'ER' 
     WHEN col4=='ERR' THEN 'ERR'
     WHEN col5=='TER' THEN 'TER'
     WHEN col6=='ERY' THEN 'ERY'
ELSE 'NER' END

，但不起作用。没有办法去做。

预期的O / P：

col1 col2 col3
--------------
AA  NM    ['ER','ERR','TER','ERY']

任何建议/提示都会很有帮助。

Answer 1

您可以使用concat_ws来使字符串看起来像数组

Select distinct(col1),col2,concat_ws('','[',
            concat_ws('', "'",col3,"',", "'",col4,"',","'",col5,"',","'",col6,"'"), 
            ']')
from  my_table

Answer 2

请尝试以下-

select col1, col2, array(
max(CASE WHEN col3=='ER'  THEN 'ER' else '' end),
max(CASE WHEN col4=='ERR' THEN 'ERR' else '' end),
max(CASE WHEN col5=='TER' THEN 'TER' else '' end), 
max(CASE WHEN col6=='ERY' THEN 'ERY' else '' end))
from table
group by col1, col2

Answer 3

这很复杂。我认为最简单的解决方法是：

select col1, col2, collect_set(col)
from ((select col1, col2, col3 as col from t
      ) union  -- intentional to remove duplicates
      (select col1, col2, col4 as col from t
      ) union  -- intentional to remove duplicates
      (select col1, col2, col5 as col from t
      ) union  -- intentional to remove duplicates
      (select col1, col2, col6 as col from t
      )
     ) t
where col is not null
group by col1, col2;

如何从Hive中的表中获取组合值

3 个答案: