Column to CSV

• scalar valued function that converts given column into comma separated values

• This approach is very intuitive and straightforward, however pretty slow

SELECT @s = isnull(@s + ', ' + CONVERT (VARCHAR(10),NumericValue), CONVERT (VARCHAR(10),NumericValue))
FROM Measurement
ORDER BY ColumnA;

SELECT SUBSTRING(
(SELECT ',' + CONVERT (VARCHAR(10),FloatValue)
FROM Measurement
ORDER BY ColumnA
FOR XML PATH('')),2,200000) AS CSV

• Comparison was performed on cca 40000 float values.
• You can see that second approach is considerably faster.

-- First approach
SQL Server Execution Times:
   CPU time = 1092 ms,  elapsed time = 1090 ms.
-- Second approach
 SQL Server Execution Times:
   CPU time = 63 ms,  elapsed time = 85 ms.