Question

Environment: Sql Server 2008

have rows of a column that contains comma separated values.

what to get the row even if a single product exists in that csv.

this is how i can do it but was just wondering if another way to write it?

SELECT * FROM REWARDS
WHERE ProductCsv like '%banana%' 
   or ProductCsv like '%strawberry%' 
   or ProductCsv like '%orange%'

Answer 1

Your current query doesn’t seem to accurately capture the results you want. What if we have a row like this:

bananaberry cream pie,strawberry shortcake,orange juice

Should this match your query or not? I think this would be more accurate:

WHERE ',' + ProductCsv + ',' LIKE '%,banana,%'
   OR ',' + ProductCsv + ',' LIKE '%,strawberry,%'
   OR ',' + ProductCsv + ',' LIKE '%,orange,%'

If you’re just trying to find one item, this is probably much more efficient:

WHERE ',' + ProductCsv + ',' LIKE '%,banana,%'

You probably want to use a split function. For example:

CREATE FUNCTION dbo.SplitStrings_XML
(
   @List   NVARCHAR(MAX),
   @Delim  NVARCHAR(255)
)
RETURNS TABLE
WITH SCHEMABINDING
AS
   RETURN 
   (  
      SELECT Item = y.i.value('(./text())[1]', 'nvarchar(4000)')
      FROM 
      ( 
        SELECT x = CONVERT(XML, '<i>' + REPLACE(@List, @Delim, '</i><i>') 
        + '</i>').query('.')
      ) AS a CROSS APPLY x.nodes('i') AS y(i)
   );
GO

So now you can say:

SELECT * FROM dbo.REWARDS AS r
WHERE EXISTS 
(
  SELECT 1 FROM dbo.REWARDS AS r2
  CROSS APPLY dbo.SplitStrings_XML(r2.ProductCsv, ',') AS x
  WHERE x.Item IN ('orange','strawberry','banana')
  AND r2.[key] = r.[key]
);

Or more simply:

SELECT DISTINCT r.ProductCsv --, other columns
  FROM dbo.REWARDS AS r
  CROSS APPLY dbo.SplitStrings_XML(r.ProductCsv, ',') AS x
  WHERE x.Item IN ('orange','strawberry','banana');

The XML approach is a little brittle depending on the kinds of strings can be stored in the table, but there are many alternatives (including passing in your set via a TVP instead of as a list or separate values). For some much deeper background on split functions see these blog posts:

http://www.sqlperformance.com/2012/07/t-sql-queries/split-strings

http://www.sqlperformance.com/2012/08/t-sql-queries/splitting-strings-follow-up

http://www.sqlperformance.com/2012/08/t-sql-queries/splitting-strings-now-with-less-t-sql

That all said, I don’t know if this is any better than what you have now.