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POsql server query concat string with '-'
 

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  1. POsql server query concat string with '-'
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    <p>In my SQL query, I'm trying to concatenate two strings in my select clause. Here's the expected results:</p> <pre><code>col A col B Result null null &amp; null '' &amp; null XYZ XYC '' null &amp; '' '' &amp; '' XYZ XYC ABC null ABC ABC '' ABC ABC XYZ ABC-XYC </code></pre> <p>My challenge is this - how do I get the 'dash' to show up for the last scenario and not the others?</p> <p>Here's my attempt:</p> <pre><code>DECLARE @ColA as varchar(10) DECLARE @ColB as varchar(10) set @ColA = null; set @ColB = null; select '&amp;' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = null; set @ColB = ''; select '&amp;' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = null; set @ColB = 'XYC'; select 'XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = ''; set @ColB = null; select '&amp;' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = ''; set @ColB = ''; select '&amp;' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = ''; set @ColB = 'XYC'; select 'XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = 'ABC';set @ColB = null; select 'ABC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = 'ABC';set @ColB = ''; select 'ABC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' set @ColA = 'ABC';set @ColB = 'XYC'; select 'ABC-XYC' as 'Expected', COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') as 'Actual' </code></pre> <p>Do you think I have to do one giant case when? I have many columns like this, and that would make it unbearable to read.</p> <p>Thanks!</p> <p>UPDATE: if I use a case when, then my select looks like this, which seems to work, but is going to be a pain.</p> <pre><code>select case when (@ColA is not null and @ColA &lt;&gt; '') and (@ColB is not null and @ColB &lt;&gt; '') then @ColA + '-' + @ColB else COALESCE(NULLIF(COALESCE(@ColA, '') + COALESCE(@ColB, ''), ''), '&amp;') end </code></pre> <p>really hoping someone has some suggestions for improvement!</p>
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    1. USRaymond
    1. USRaymond
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    1. COWhat version of SQL Server?
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      1. USMartin Smith
    2. COunfortunately, sql 2000... (though curious, is there some new feature in the later versions of SQL Server that will solve this problem?)
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      1. USRaymond
    3. COSQL Server 2012 has `CONCAT` which might have made things marginally simpler.
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      1. USMartin Smith
 

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