我有一张桌子

create table us
(
 a number
);

现在我有如下数据:

a
1
2
3
4
null
null
null
8
9

现在我需要一个查询来计算列a中的空值和非空值


当前回答

SELECT
    ALL_VALUES
    ,COUNT(ALL_VALUES)
FROM(
        SELECT 
        NVL2(A,'NOT NULL','NULL') AS ALL_VALUES 
        ,NVL(A,0)
        FROM US
)
GROUP BY ALL_VALUES

其他回答

下面是一个在Oracle上运行的快速而简单的版本:

select sum(case a when null then 1 else 0) "Null values",
       sum(case a when null then 0 else 1) "Non-null values"
from us

这里有两种解决方案:

Select count(columnname) as countofNotNulls, count(isnull(columnname,1))-count(columnname) AS Countofnulls from table name

OR

Select count(columnname) as countofNotNulls, count(*)-count(columnname) AS Countofnulls from table name

在阿尔贝托的基础上,我添加了汇总。

 SELECT [Narrative] = CASE 
 WHEN [Narrative] IS NULL THEN 'count_total' ELSE    [Narrative] END
,[Count]=SUM([Count]) FROM (SELECT COUNT(*) [Count], 'count_nulls' AS [Narrative]  
FROM [CrmDW].[CRM].[User]  
WHERE [EmployeeID] IS NULL 
UNION
SELECT COUNT(*), 'count_not_nulls ' AS narrative 
FROM [CrmDW].[CRM].[User] 
WHERE [EmployeeID] IS NOT NULL) S 
GROUP BY [Narrative] WITH CUBE;

这适用于Oracle和SQL Server(你可能可以让它在其他RDBMS上工作):

select sum(case when a is null then 1 else 0 end) count_nulls
     , count(a) count_not_nulls 
  from us;

Or:

select count(*) - count(a), count(a) from us;

对于非空值

select count(a)
from us

null值

select count(*)
from us

minus 

select count(a)
from us

因此

SELECT COUNT(A) NOT_NULLS
FROM US

UNION

SELECT COUNT(*) - COUNT(A) NULLS
FROM US

应该做这项工作

更好的是列标题是正确的。

SELECT COUNT(A) NOT_NULL, COUNT(*) - COUNT(A) NULLS
FROM US

在我的系统上进行的一些测试中,需要进行全表扫描。