Question

如果我执行此查询，我将获得输出，但不是所需的输出。我想得到输出：

FirstName                            LastName


ADT                                  NULL 
----------------------------------------------------------------------------

这是我的问题：

DECLARE @FullName VARCHAR(100)

SET @FullName = 'ADT'

SELECT SUBSTRING(@FullName, 1, NULLIF(CHARINDEX(' ', @FullName) - 1, -1)) AS [FirstName],

SUBSTRING(@FullName, CHARINDEX(' ', @FullName) + 1, LEN(@FullName)) AS [LastName]

此查询的输出是：

FirstName    LastName

NULL           ADT
------------------------------------------

提前感谢您的帮助。

Answer 1

两个选项：

如果@FullName包含空格

或

通过在末尾添加空格来删除特殊情况。

declare @fullName varchar(100) = 'ADT'
select 
    LEFT(@fullName, charindex(' ',@fullName+' ')-1) as FirstName,
    SUBSTRING(@fullname,charindex(' ',@fullName+' ')+1,LEN(@fullname)) as last

Answer 2

也许不是最有效但符合要求的。

DECLARE @FullName VARCHAR(100)

SET @FullName = 'ADT'

SELECT SUBSTRING(@FullName, 0, ISNULL(NULLIF(CHARINDEX(' ', @FullName), 0), LEN(@FullName) + 1)) AS [FirstName]
, SUBSTRING(@FullName, NULLIF(CHARINDEX(' ', @FullName) + 1, 1), LEN(@FullName) - CHARINDEX(' ', @FullName) + 1) AS [LastName]

以下是基于澄清要求的更新声明。 REVERSE字符串函数派上用场，LTRIM是由LastName列上的前导空格问题引起的。

DECLARE @FullName VARCHAR(100)

SET @FullName = 'ADT SAMPLE DATABASE CASE'

SELECT SUBSTRING(@FullName, 0, ISNULL(NULLIF(LEN(@FullName) + 1 - CHARINDEX(' ', REVERSE(@FullName)), 0), LEN(@FullName) + 1)) AS [FirstName]
, LTRIM(SUBSTRING(@FullName, NULLIF(LEN(@FullName) - CHARINDEX(' ', REVERSE(@FullName)), LEN(@FullName)) + 1, LEN(@FullName) - (LEN(@FullName) - CHARINDEX(' ', REVERSE(@FullName))))) AS [LastName]

Answer 3

你的意思是ADT SAMPLE DATABASE AS FirstName和CASE AS LastName

T-SQL查询问题？

3 个答案: