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sqlserver对字段出现NULL值的处理
来源: 互联网 发布时间:2014-10-04
本文导语: 代码如下: -判断某些字段是否为空 --case select case when '字段名' is null then 'N' else convert(varchar(20),'字段名') end as 'NewName' select case when null is null then 'N' else convert(varchar(20),null) end as 'NewName' --SQL Server 2005:coalesce select coalesce('字符串...
代码如下:
-判断某些字段是否为空
--case
select case when '字段名' is null then 'N' else convert(varchar(20),'字段名') end as 'NewName'
select case when null is null then 'N' else convert(varchar(20),null) end as 'NewName'
--SQL Server 2005:coalesce
select coalesce('字符串类型字段','N') as 'NewName'
select coalesce(convert(varchar(20),'非字符串类型字段'),'N') as 'NewName'
select coalesce(convert(varchar(20),null),'N') as 'NewName'
--coalesce,返回其参数中的第一个非空表达式
select Coalesce(null,null,1,2,null)union
select Coalesce(null,11,12,13,null)union
select Coalesce(111,112,113,114,null)