如题：如何简单的判断表中符合条件的某列是全为null 还是部分为null
例如表 table1(a,b,c) 如何简单判断当a=1的时候的所有数据 c是全为空还是部分为空
------解决方案--------------------
----------------------------------------------------------------
-- Author :DBA_HuangZJ(发粪涂墙)
-- Date :2014-06-26 15:57:06
-- Version:
-- Microsoft SQL Server 2008 R2 (SP2) - 10.50.4000.0 (X64)
-- Jun 28 2012 08:36:30
-- Copyright (c) Microsoft Corporation
-- Enterprise Edition (64-bit) on Windows NT 6.2 <X64> (Build 9200: ) (Hypervisor)
--
----------------------------------------------------------------
--> 测试数据[huang]
if object_id('[huang]') is not null drop table [huang]
go
create table [huang]([a] int,[c] nvarchar(2))
insert [huang]
select 1,null union all
select 1,null union all
select 2,null union all
select 2,'a'
--------------生成数据--------------------------
select COUNT(c)[全部null]
from [huang]
WHERE a=1
SELECT COUNT(c)[部分null]
FROM huang
WHERE a=2
----------------结果----------------------------
/*
全部null
-----------
0
(1 row(s) affected)
部分null
-----------
1
*/