Sql server 带“-”的sql server查询concat字符串

在SQL查询中，我试图在select子句中连接两个字符串。以下是预期结果：

col A   col B   Result
null    null    &
null    ''      &
null    XYZ     XYC
''      null    &
''      ''      &
''      XYZ     XYC
ABC     null    ABC
ABC     ''      ABC
ABC     XYZ     ABC-XYC

我的挑战是——如何让“冲刺”在最后一个场景中出现，而不是在其他场景中出现

以下是我的尝试：

DECLARE @ColA as varchar(10)
DECLARE @ColB as varchar(10)

set @ColA = null; set @ColB = null;  select '&'   as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = null; set @ColB = '';    select '&'   as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = null; set @ColB = 'XYC'; select 'XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = '';   set @ColB = null;  select '&'   as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = '';   set @ColB = '';    select '&'   as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = '';   set @ColB = 'XYC'; select 'XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = 'ABC';set @ColB = null;  select 'ABC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = 'ABC';set @ColB = '';    select 'ABC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'
set @ColA = 'ABC';set @ColB = 'XYC'; select 'ABC-XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&') as 'Actual'

你认为我什么时候必须做一个大案子？我有很多这样的专栏，这会让人难以阅读

谢谢

更新：如果我使用case-when，那么我的选择看起来是这样的，这看起来很有效，但会很痛苦

select 
    case when (@ColA is not null and @ColA <> '') and
          (@ColB is not null and @ColB <> '') 
        then @ColA + '-' + @ColB
        else COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&')
    end

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真希望有人能提出一些改进的建议

您可以使用这样的搜索案例函数吗

Select Case When isnull(ColA, '') + isnull(ColB, '') == '' Then '&'
            When isnull(ColA, '') <> '' and isnull(ColB, '') <> '' Then ColA + '-' + ColB
            Else isnull(ColA, '') + isnull(ColB, '')
From Table1

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我认为这个答案与其他答案没有太大区别，但你可以试试这个：

SELECT
CASE
    WHEN NULLIF(ColA,'') <> '' AND NULLIF(ColB,'') <> ''
        THEN ColA + '-' + ColB
    WHEN NULLIF(ColA,'') <> '' OR NULLIF(ColB,'') <> ''
        THEN COALESCE(ColA,ColB)
    ELSE '&'
END

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什么版本的SQL Server？不幸的是，SQL 2000。。。尽管好奇，SQL Server的更高版本中是否有一些新功能可以解决这个问题？SQL Server 2012有CONCAT，这可能会使事情稍微简单一些。