How can I pull a list of ID's from a SQL table as a comma-separated values string?

Question

I have to pull a list of integer IDs from a table using only records that match some criteria. For example:

Select ProdID From Products Where (ProdType='XYZ'); 

The catch is that I have to return it as a set of comma separated values so I can use it to select items in a multi-select list:

111,231,554,112 

rather than as records. I do not want to do this in my C# code - I'd like it to come right out of the database via a query this way. Any ideas?

Answer 1

MySQL

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SELECT GROUP_CONCAT(t.prodid SEPARATOR ',')   FROM PRODUCTS t  WHERE t.prodtype = 'XYZ' 

Oracle:

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There is an excellent summary of the available string aggregation techniques on Tim Hall's site.

SQL Server 2005+

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SELECT STUFF((SELECT ','+ t.prodid                 FROM PRODUCTS t                WHERE t.prodtype = 'XYZ'              FOR XML PATH('')), 1, 1, '') 

Answer 2

In addition to @OMG Ponies method, you could also try this COALESCE trick from:

Using COALESCE to Build Comma-Delimited Strings

declare @string nvarchar(255)  select @string = coalesce(@string + ', ', '') + cast(prodid as nvarchar(5)) from products