HIVE ：行列转换

举个栗子

a b 1
a b 2
a b 3
c d 4
c d 5
c d 6
<==>
a b 1,2,3
c d 4,5,6

行转列 ==>

select 
col1,
col2,
concat_ws(',',collect_set(col3)) 
from table_test  
group by col1,col2;

列转行 <==

select col1, col2, col5
from table_test a
lateral  view explode(split(col3,','))  b AS col5

附： HQL中的concat函数,concat_ws函数，concat_group函数之间的区别