Question

我需要检查列中间名是否包含任何值。如果它是空的，那么它不应该与名称连接。

    Select
     ..
     Agent,
     FirstName + ' ' MiddleName + ' ' + LastName as Name,
     ...
     from tbSystemUser

在上面的查询中，如果MiddleName为空，则会在Name中添加两次空格。

Answer 1

您可以在CASE expression中使用COALESCE：

 select
 ..
 Agent,
 case when coalesce(MiddleName, '') = '' then FirstName + ' ' + LastName 
      else FirstName + ' ' + MiddleName + ' ' + LastName 
 end as Name,
 ...
 from tbSystemUser

Answer 2

您可以使用案例陈述

Select
     ..
     Agent,
     Case MiddleName
     when ' ' then
     FirstName + ' ' + LastName 
     else
     FirstName + ' ' MiddleName + ' ' + LastName
     end
     as Name,
     ...
     from tbSystemUser

OR

Select
         ..
         Agent,
         Case 
         when MiddleName = ' ' then
         FirstName + ' ' + LastName 
         else
         FirstName + ' ' MiddleName + ' ' + LastName
         end
         as Name,
         ...
         from tbSystemUser

Answer 3

Select
 ..
 Agent,
 FirstName + CASE WHEN MiddleName is not null THEN  ' ' + MiddleName else '' END  + ' ' + LastName as Name,
 ...
 from tbSystemUser

Answer 4

如果MiddleName不为null，则使用case表达式仅添加MiddleName + ' '部分：

Select
     ...
     Agent,
     FirstName +
     case when MiddleName is not null then MiddleName + ' ' end +
     LastName as Name,
     ...
     from tbSystemUser

Answer 5

我相信你可以这样使用子查询：

 Select Agent, Name from
 (
     Select t1.Agent as Agent, t1.FirstName + ' ' t1.MiddleName + ' ' + t1.LastName as Name,
     from tbSystemUser as t1 WHERE t1.MiddleName IS NOT NULL
 )
 NATURAL JOIN 
 (
      Select t2.Agent as Agent, t2.FirstName + ' ' + t2.LastName as Name,
      from tbSystemUser as t2 WHERE t2.MiddleName IS NULL
 )

这将根据两个选择创建的名称构建您的答案。

Answer 6

SELECT FirstName 
   +IIF(ISNULL(LTRIM(RTRIM(MiddleName)),'')<>'',' '+MiddleName,'')
   +' '+LastName as Name

或者，如果您的SQL Server版本早于2012年：

SELECT FirstName 
   +CASE WHEN ISNULL(LTRIM(RTRIM(MiddleName))) <> '' 
      THEN ' '+MiddleName
      ELSE '' END
   +' '+LastName as Name

你没有指明空的意思。与此处的大多数其他解决方案不同，这将处理任何长度的空字符串，包括空值，但不处理特殊字符。我会假设没人去，并添加换行符作为中间名？：）

如何检查选择查询中的列中的值

6 个答案: