Hive，SQL：爲Hive表中100列以上的每一列返回NULL值COUNT

Question

返回Hive表中100列以上每列的NULL值的COUNT值的SQL代碼是什麼？

Answer 1

在SQL這將是

SELECT 
    SUM(CASE WHEN a is null then 1 else 0 end) as a_null_count, 
    SUM(CASE WHEN b is null then 1 else 0 end) as b_null_count,  
    --- ... 
    SUM(CASE WHEN z is null then 1 else 0 end) as z_null_count 
FROM table