计算Oracle表中3列的null和非null计数

Question

我在表格中有3列：

v_type1|v_type2|v_type3

这些列可以包含NULL。我需要的是计算3列中每一列的NULL和NOT NULL值的数量。结果必须是一行（实际上有6列）：

v_type1_null_counts|v_type1_notnull_counts|v_type2_null_counts|v_type2_notnull_counts|v_type3_null_counts|v_type3_notnull_counts

我尝试加入但未完成结果。 我需要做什么？

Answer 1

select c1 as v_type1_notnull_cnt,  
       total - c1 as v_type1_null_cnt,
       c2 as v_type2_notnull_cnt,
       total - c2 as v_type2_null_cnt,
       c3 as v_type3_notnull_cnt ,
       total - c3 as v_type3_null_cnt
from (
   select  count(*) as  total, 
           count(v_type1) as c1,
           count(v_type2) as c2,
           count(v_type3) as c3
   FROM your_table
) t

Answer 2

count()计算非NULL值。所以最简单的方法是：

select count(v_type1) as v_type1_not_null,
       count(v_type2) as v_type2_not_null,
       count(v_type3) as v_type3_not_null,
       (count(*) - count(v_type1)) as v_type1_null,
       (count(*) - count(v_type2)) as v_type2_null,
       (count(*) - count(v_type3)) as v_type3_null
from t;