--判断某些字段是否为空--caseselect 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：coalesceselect 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)unionselect Coalesce(null,11,12,13,null)unionselect Coalesce(111,112,113,114,null)
